Species Of Gram-positive Cocci Research Articles

Analysis of late-onset neonatal sepsis cases in a level three neonatal intensive care unit.

OBJECTIVE:Newborns in neonatal intensive care units (NICUs) are at high risk for developing nosocomial infections (NIs), which may result in morbidity and mortality. In this study, we aimed to ascertain the bacteriological profiles and their antimicrobial susceptibility patterns in NIs.METHODS:We conducted a cross-sectional study in the NICU. Late-onset sepsis (LOS) cases confirmed with blood cultures were evaluated retrospectively. Laboratory parameters, demographics, and clinical data were collected and analyzed from hospital records retrospectively.RESULTS:Of the 1210 infants in the NICU, 76 (6.3%) had LOS. A total of 86 episodes of LOS were documented; in 10 infants, two pathogens were identified. The mean gestational age (GA) of the infants with LOS was 33.2±4.8 weeks (23 to 42 weeks). Gram-positive cocci (GPC) caused most of the LOS episodes (65.8%, 50/76), with coagulase-negative Staphylococcus (CoNS) as the most common cause of LOS (50%, 38/76). Gram-negative rod species (GNRs) accounted for 32.9% (25/76) of the LOS cases, and fungi accounted for 1.3% (1/76). The mortality rates for GNR and GPC were 17.9% and 6.4%, respectively (p>0.05). The mean CRP and conjugated bilirubin levels for the GPC and GNR groups were 37.5 vs. 29.5 mg/dl and 0.7 vs 1.5 mg/dl, respectively (p>0.05). GNRs had a 20–25% ceftriaxone resistance. Two (4%) GPC species were resistant to linezolid, while all were susceptible to vancomycin. All of the GNRs were susceptible to carbapenems.CONCLUSION:These results underscore the recent emergence of CoNS in NICUs. LOS due to GNRs seems to display higher C-reactive protein and conjugated bilirubin values than those due to GPC. Clinical monitoring of NIs and bacterial resistance profiles are required in all NICUs.

Gastrointestinal Microbial Flora in Wild and Captive Olive Baboons (<i>Papio </i><i>a</i><i>nubis</i>)

Background: Vertebrate gut microbiota plays essential roles in host biology, including immune regulation, energy acquisition, vitamin synthesis and disease risk. There are however several other pathogenic microorganisms found in the gut and are transmissible by fecal oral route. About 60% of all human diseases and approximately 75% of emerging infectious diseases are zoonotic. Due to an observed increase in conflicts and interactions between human and nonhuman primates, both are at risk of pathogen transfer and infection. Methods: This study was conducted on 50 captive baboons and 67 wild baboons. Stool samples were collected and cultured and species identification of each isolate was done by the use of Analytical Profile Indexing tool. Results: Species of Gram-positive cocci, Gram-positive and Gram-negative rods were identified, with more isolates being obtained from wild than captive baboon fecal samples. Unlike the Gram-negative rods, the captive baboons harbored more Gram-positive cocci and Gram-positive rods than the wild baboons. Escherichia coli was the most dominant isolate and was collected in more than 50% of the samples from both groups of animals. Of the Gram-positive cocci and Gram-positive rods, Aerococcus viridans, Bacillus cereus and Bacillus firmus were found to be the most common isolates in both groups of animals. Conclusion: Though the wild and captive baboons harbor different gastrointestinal bacteria, similarities do occur. The wild baboons have a richer microbial diversity as compared to the captive baboons.

Pengenalpastian Mikroflora Bakteria Gram Positif dan Negatif yang Dipencil daripada Kolam Air Panas Bentong, Pahang

A study on the isolation and identification of bacterial flora from hot spring was carried out from Bentong hot spring water, Pahang. In general, many of the bacteria identified from the hot spring were from Bacillus sp. due to its ability to adapt to high temperature mainly by forming endospore. The objective of this study was to identify bacteria other than Bacillus sp. that were able to survive this hot spring. Three hot spring pools were identified as A,B and C. The temperatures were ranging from 36°C to 52°C and their pH values were between 7.88-8.65. The result shows that two species of Gram positive cocci and three species of Gram negatives were isolated. The two Gram positives were Streptococcus sp. and Staphylococcus sp. The three species of Gram negative rods were identified as Pseudomonas sp., Klebsiella sp. and Proteus sp. In conclusion, non-sporulating species of bacteria other than Bacillus sp. have adapted to survive in hot springs.

Kocuria uropygioeca sp. nov. and Kocuria uropygialis sp. nov., isolated from the preen glands of Great Spotted Woodpeckers (Dendrocopos major)

Two new species of Gram-positive cocci were isolated from the uropygial glands of wild woodpeckers (Dendrocopos major) originating from different locations in Germany. A polyphasic approach confirmed the affiliation of the isolates to the genus Kocuria. Phylogenetic analysis based on the 16S rRNA gene showed high degree of similarity to Kocuria koreensis DSM 23367T (99.0% for both isolates). However, low ANIb values of <80% unequivocally separated the new species from K. koreensis. This finding was further corroborated by DNA fingerprinting and analysis of polar lipid profiles. Furthermore, growth characteristics, biochemical tests, MALDI-TOF MS analysis, and G+C contents clearly differentiated the isolates from their known relatives. Besides, the woodpecker isolates significantly differed from each other in their whole-cell protein profiles, DNA fingerprints, and ANIb values. In conclusion, the isolated microorganisms constitute members of two new species, for which the names Kocuria uropygioeca sp. nov. and Kocuria uropygialis sp. nov. are proposed. The type strains are 36T (DSM 101740T=LMG 29265T) and 257T (=DSM 101741T=LMG 29266T) for K. uropygialis sp. nov. and K. uropygioeca sp. nov., respectively.

Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.

Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.

Utilización de MALDI-TOF en el diagnóstico rápido de la sepsis

The introduction of mass spectrometry through MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) in the diagnosis of bacteraemia and fungaemia has represented a revolution due to the rapidity and reliability of the results that it can offer to microbiology services and laboratories through analysis of the mass spectrum of the bacterial protein directly from positive blood culture bottles. These data are more useful if they are used in conjunction with other techniques able to identify the antibiotic resistance pattern of the microorganism. There is a need for a process of standardising sample processing protocols and for perfecting the identification of the agents causing bacteraemia, especially in some species of Gram-positive cocci and in polymicrobial processes. The introduction of this methodology provides rapid information that is highly important for the clinical management of bacteraemia. The availability of a multidisciplinary working group that applies all this information quickly and correctly in hospitals will improve the quality of care, reduce antibiotic expenditure and hospital stay and help to control the serious problem of antibiotic resistance.

Mechanisms of Resistance to Antimicrobial Drugs in Pathogenic Gram-Positive Cocci

Many species of Gram-positive cocci are pathogenic. The most important are staphylococci, streptococci, and enterococci. Widespread usage of antibiotics was the main cause for the appearance and spread of resistance to almost all antimicrobials. The occurrence, mechanisms, and genetic background of resistance to antimicrobial drugs other than beta-lactams and glycopeptides among pathogenic staphylococci, streptococci, and enterococci are discussed in the text. Well-established agents (such as macrolides, lincosamides, streptogramins, aminoglycosides, quinolones, mupirocin, chloramphenicol) as well as new agents (linezolid, daptomycin, quinupristine/dalfopristine, ratapamulin, tigecycline, iclaprim and new generations of quinolones) are considered.

Adherence of Staphylococcus aureus fibronectin binding protein A mutants: an investigation using optical tweezers

Bacterial adhesion to extracellular matrix proteins plays a major role in infections of host tissue and medical devices. In some species of gram-positive cocci, this adhesion is mediated by specific molecules present on the bacterial cell surface. We have used optical tweezers to dynamically measure the adhesive force between an individual Staphylococcus aureus bacterium and a fibronectin-coated surface. A bacterium was optically trapped and brought in contact with a 10-μm diameter polystyrene microsphere coated with fibronectin. The force required to detach the cell from the microsphere was measured by tracking the displacement signals of the trapped cell on a quadrant photodiode throughout the detachment process for a series of S. aureus strains expressing fibronectin-binding proteins with various degrees of mutation. The single-bond rupture forces ranged between 15 and 26 pN depending on the extent of mutation. No binding was observed in the strain with the highest degree of mutation. These results confirm that multiple regions of the S. aureus fibronectin adhesin participate in the binding process and provide further insight into the role of these regions in the adhesive process.

Comparison of Three Commercial Rapid Identification Systems for the Unusual Gram-Positive Cocci Dolosigranulum pigrum, Ignavigranum ruoffiae, andFacklamia Species

We evaluated three rapid identification systems—The Biomerieux rapid ID 32 STREP (ID32), the BBL Crystal rapid gram-positive identification (Crystal), and the Remel IDS RapID STR (IDS) systems—for their ability to identify 7 strains of Alloiococcus otitidis, 27 strains of Dolosigranulum pigrum, 3 strains of Ignavigranum ruoffiae, and 18 strains of 4 different Facklamia species. Since none of these six species of gram-positive cocci are included in the identification databases for these systems, the correct identification for the strains tested should be “unacceptable ID” for the ID32 and Crystal systems or “no choice” for the IDS system. The ID32 system identified all 27 strains of D. pigrum, 6 of 18 Facklamiaspecies, and 2 of 3 cultures of I. ruoffiae as “unacceptable ID.” The Crystal system identified 10 of 27 D. pigrum, 2 of 18 Facklamia species, and 2 of 3I. ruoffiae strains as “unacceptable ID.” The IDS system identified only 1 culture of D. pigrum as “no choice,” but it also identified 2 cultures of D. pigrumas a “questionable microcode” and 19 cultures of D. pigrum as an “inadequate ID, E. faecalis 90%,S. intermedius 9%.” A total of 2 of the 18 cultures ofFacklamia and all 3 of the I. ruoffiaecultures were correctly identified as “no choice.” The most common misidentifications of Facklamia species by the ID32 and IDS systems were as various Streptococcus species and asGemella species. In the Crystal system, the most common erroneous identification was Micrococcus luteus. These data indicate the need for the commercial manufacturers of these products to update their databases to include newly described species of gram-positive cocci.

In vitro activity of RP 59500, a semisynthetic injectable pristinamycin, against staphylococci, streptococci, and enterococci

The in vitro activity of RP 59500, a semisynthetic pristinamycin, was compared with the activities of vancomycin, oxacillin, ampicillin, gentamicin, ciprofloxacin, and rifampin against five Staphylococcus species, five Streptococcus species, and four Enterococcus species. For staphylococci, MICs were 0.13 to 1 microgram/ml and the MICs for 90% of the strains tested (MIC90s) were 0.13 to 0.5 microgram/ml; there were no differences between oxacillin-susceptible and -resistant strains. For streptococci, MICs were 0.03 to 4 micrograms/ml and MIC90s were 0.25 to 2 micrograms/ml; viridans group streptococci were the least susceptible streptococci. For enterococci, MICs were 0.25 to 32 micrograms/ml and MIC90s were 2 to 4 micrograms/ml; Enterococcus faecalis was the least susceptible. Vancomycin was the only comparative drug with consistent activity against all species of gram-positive cocci. With RP 59500, raising the inoculum 100-fold, lowering the pH of cation-adjusted Mueller-Hinton broth to 5.5, or omitting cation supplementation had little effect on MICs, but 50% serum increased MICs 2 to 4 dilution steps. The differences between MBCs and MICs were greater for staphylococci and enterococci than for streptococci. Time-kill studies with 24 strains indicated that RP 59500 concentrations 2-, 4-, and 16-fold greater than the MICs usually killed bacteria of each species at similar rates; reductions in CFU per milliliter were less than those observed with oxacillin or vancomycin against staphylococci and less than those observed with ampicillin against enterococci. RP 59500 antagonized the bactericidal activities of oxacillin and gentamicin against Staphylococcus aureus ATCC 29213 and that of ampicillin against E. faecalis ATCC 29212. Against the latter, combination with gentamicin was indifferent. RP 59500 has a broad spectrum of in vitro activity against gram-positive cocci; combining it with other drugs is not advantageous.

Alterations in lactate dehydrogenase isoenzyme patterns after therapy with streptokinase or streptococcal infection.

Serum samples from patients receiving intravenous streptokinase were examined for evidence of interaction in vivo between streptokinase and lactate dehydrogenase (EC 1.1.1.27; LD). We found that this treatment produced a band of LD activity that remained at the electrophoretic origin of LD isoenzyme analysis. Treatment with tissue plasminogen activator produced no such band. The streptokinase-LD complex could be removed from serum by ultracentrifugation. It remained in the circulation for as long as 48 h after streptokinase infusion. A similar phenomenon was observed in a case of pneumococcal sepsis. Examination of supernates from both cultures of several species of Gram-positive cocci revealed interactions between human LD and Streptococcus groups A and C and also Streptococcus pneumoniae. Evidently streptokinase can form complexes with LD in vivo after either streptokinase therapy or infection, with consequent alteration of the LD isoenzyme pattern.

New receptor for human plasminogen on gram positive cocci

180 bacterial strains representing 17 different species of gram positive cocci were tested for the ability to interact with human plasminogen. Receptors for plasminogen could be detected on 23/24 strains of S. pyogenes, 15/15 strains of S. equisimilis, 14/16 strains of human group G streptococci and 14/14 strains of S. pneumoniae. Eight of nineteen strains representing five species of alpha-hemolytic streptococci were also positive. S. equisimilis demonstrated the highest uptake with a median value of 58 per cent (20%-67%). On the other hand, all strains of S. agalactiae, the majority of S. faecalis and all S. aureus, S. epidermidis and S. saprophyticus strains tested were negative. The concentration of unlabelled plasminogen causing a 50 per cent reduction of bound tracer was between 50 and 150 mM. These estimates of the dissociation constant confirmed the specific nature of the interaction. Binding of plasminogen could be blocked by addition of plasmin-aprotinin complex, suggesting that plasminogen and plasmin bind to the same receptor. Binding was also blocked by the plasminogen fragment kringle 1-3, but not by miniplasminogen, a fragment containing kringle 5 and the B-chain region. As streptokinase interacts mainly with the B-chain of plasmin it is clear that the bacterial receptor for plasminogen is not identical to streptokinase.

Reversal of activity of trimethoprim against gram-positive cocci by thymidine, thymine and 'folates'.

The reversal of the antibacterial activity of trimethoprim against different species of Gram-positive cocci (Staphylococcus aureus, Staph. epidermidis, Staph. saprophyticus, group B streptococci, Streptococcus faecalis and Str. faecium) by thymine, thymidine and various 'folates' (folate, folinate, dihydrofolate and tetrahydrofolate) was tested. Against group B streptococci and staphylococci only thymidine antagonized trimethoprim. However, for enterococci, thymine, thymidine, dihydrofolate, tetrahydrofolate and folinate all reversed the activity of trimethoprim, although by different amounts. Dihydrofolate was significantly more effective as a trimethoprim antagonist for Str. faecium than for Str. faecalis. While thymine and thymidine caused the MIC of trimethoprim against enterococci to increase more than 100-fold--thereby rendering them resistant--the 'folates' brought about much smaller increases in trimethoprim MIC, in the order of ten-fold only. Thus, even in the presence of 'folates' enterococci remain sensitive in vitro to trimethoprim.

Thiolactomycin, a new antibiotic. III. In vitro antibacterial activity.

Thiolactomycin is a new broad-spectrum antibiotic, active in vitro against many species of Gram-positive cocci, Enterobacteriaceae, Haemophilus, acid-fast bacteria and anaerobic bacteria. However, the activity is generally moderate and bacteriostatic in action. This antibiotic eludes cross resistance with any of the known antibacterial drugs such as ampicillin, carbenicillin or cycloserine. The effect on Gram-negative bacilli in vitro is little affected by the inoculum size, the presence of horse serum, the pH of the medium or the type of medium. When thiolactomycin was added to the assay medium, the minimum inhibitory concentration of ampicillin against inducible beta-lactamase producing strains of Staphylococcus aureus and Pseudomonas aeruginosa was reduced. Thiolactomycin inhibited the production of inducible beta-lactamase in several organisms.

Extractable antigen shared by Peptostreptococcus anaerobius strains.

Extracts from several species of gram-positive cocci were prepared by a modification of the Rantz-Randall autoclave method and tested for reactions with rabbit anti-Peptostreptococcus anaerobius (ATCC 27337 and VPI 5737) sera in a capillary precipitin test. Antigen preparations from two reference strains of P. anaerobius (ATCC 27337 and VPI 5737) and six clinical isolates of P. anaerobius reacted with the P. anaerobius antisera. These extracts formed a line of identity by immunodiffusion and displayed at least one precipitin line by immunoelectrophoresis. Absorption of the antisera with either the autoclaved extract or a 10% whole-cell suspension from each of the eight P. anaerobius strains removed the precipitin line(s) observed during immunodiffusion and immunoelectrophoresis. Extracts prepared to other species of Peptococcus, Peptostreptococcus, and Streptococcus did not react with the P. anaerobius antisera in a capillary precipitin test. In addition antisera to Lancefield groups A to G did not react with the extracts from the eight P. anaerobius strains. Preliminary chemical analysis of the extracts from the eight strains showed that they contained approximately 0.2 mg of carbohydrate per ml and 3.6 mg of protein per ml. The rabbit anti-P. anaerobius sera used in this study detected a common antigen(s) shared by strains of P. anaerobius, but did not react with autoclave extracts prepared from other species of gram-positive cocci. This extractable antigen could be used in a capillary precipitin test to rapidly identify P. anaerobius strains isolated in the clinical microbiology laboratory.

Bacterial interference by oropharynegeal and clinical isolates of anaerobic bacteria.

Anaerobic isolates were tested for bacterial inhibitory activity. Of 144 isolates, 102 were from oropharynegeal washings, and 42 were from clinical specimens. Thirteen facultative bacterial species (seven members of the Enterobacteriaceae and six species of gram-positive cocci) were used as indicators of inhibition. Eleven anaerobic species were isolated from oral secretions. All isolates of Bacteroides melaninogenicus, the most commonly recovered species, consistently inhibited several species of indicator bacteria. Bacteroides fragilis, Bacteroides oralis, and Peptostreptococcus anaerobius had unprecictable inhibitory activity, whereas most of the other oral anaerobes were noninhibitory. The 42 clinical species were generally noninhibitory.

Inhibitory effect in vitro of sodium polyanethol sulfonate on the growth of Neisseria meningitidis.

The influence of 0.05% sodium polyanethol sulfonate on the growth of 24 strains of Neisseria meningitidis in broth medium was examined; several of the strains were markedly inhibited. A paper disk method was evolved for screening the sensitivity of various bacteria to sodium polyanethol sulfonate on solid medium; the highest sensitivity was observed in N. meningitidis and Neisseria gonorrhoeae. Zones of growth inhibition were also observed in a proportion of strains in certain species of gram-positive cocci, whereas all gram-negative bacilli were uniformly resistant. The implications of these observations for the routine use of sodium polyanethol sulfonate in blood culture media are discussed.