ANTIBACTERIAL ACTIVITY OF LINCOMYCIN AND PRISTINAMYCIN: A COMPARISON WITH ERYTHROMYCIN

Preparation and evaluation in vitro and in vivo of pristinamycin enteric-coated granules based on albumin nanoparticles

CONTEXT

The purpose of this study was to prepare enteric-coated particles based on albumin nanoparticles (NPs) using a mixture of PI_A albumin NPs freeze-dried powder (PA-PI_A) and PII_A albumin NPs freeze-dried powder (PA-PII_A) to improve the bioavailability effect of pristinamycin.

OBJECTIVE

This is the first study on the preparation of pristinamycin into enteric-coated granules based on albumin NPs, and our study has effectively improved the bioavailability of pristinamycin and ensured its safety.

METHODS

Pristinamycin albumin enteric-coated granules (PAEGs) were prepared by hybrid wet granulation. The characterizations of albumin NPs were performed by in vitro and in vivo studies of PAEGs. The assays were analyzed using zeta-sizer, transmission electron microscopy, high-performance liquid chromatography, and a fully automated biochemical index analyzer.

RESULTS

The morphology of NPs was close to spherical. PI_A-NPs and PII_A-NPs respectively had a zeta potential of (-24.33 ± 0.75) mV and (+7.30 ± 0.27) mV and mean size of (251.91 ± 19.64) nm and (232.83 ± 22.61) nm. The release of PI_A and PII_A from PAEGs in the artificial gastrointestinal fluid was as high as 58.46% and 87.79%. In the experimental group of oral PAEGs, PI_A and PII_A were AUC_(0-t) (3.68 ± 0.58) mg·L^-1·h^-1 and (2.81 ± 1.06) mg·L^-1·h^-1. The results of aspartate aminotransferase and alanine aminotransferase biochemical indices showed that there was no significant difference between the experimental and normal groups of oral PAEGs.

CONCLUSION

The PAEGs significantly increased the release of PI_A and PII_A in simulated intestinal fluid and improved the bioavailability. The oral administration of PAEGs may not damage the liver of rats. We hope that our study will promote its industrial development or clinical application.

Shielding the Next Generation: Symbiotic Bacteria from a Reproductive Organ Protect Bobtail Squid Eggs from Fungal Fouling

Organisms must have strategies to ensure successful reproduction. Some animals that deposit eggs protect their embryos from fouling/disease with the help of microorganisms. Although beneficial bacteria are hypothesized to contribute to egg defense in some organisms, the mechanisms of this protection remain largely unknown, with the exception of a few recently described systems. Using both experimental and analytical approaches, we demonstrate that symbiotic bacteria associated with a cephalopod reproductive gland and eggs inhibit fungi. Chemical analyses suggest that these bacteria produce antimicrobial compounds that may prevent overgrowth from fungi and other microorganisms. Given the distribution of these symbiotic glands among many cephalopods, similar defensive relationships may be more common in aquatic environments than previously realized. Such defensive symbioses may also be a rich source for the discovery of new antimicrobial compounds.

The importance of defensive symbioses, whereby microbes protect hosts through the production of specific compounds, is becoming increasingly evident. Although defining the partners in these associations has become easier, assigning function to these relationships often presents a significant challenge. Here, we describe a functional role for a bacterial consortium in a female reproductive organ in the Hawaiian bobtail squid, Euprymna scolopes. Bacteria from the accessory nidamental gland (ANG) are deposited into the egg jelly coat (JC), where they are hypothesized to play a defensive role during embryogenesis. Eggs treated with an antibiotic cocktail developed a microbial biomass primarily composed of the pathogenic fungus Fusarium keratoplasticum that infiltrated the JC, resulting in severely reduced hatch rates. Experimental manipulation of the eggs demonstrated that the JC was protective against this fungal fouling. A large proportion of the bacterial strains isolated from the ANG or JC inhibited F. keratoplasticum in culture (87.5%), while a similar proportion of extracts from these strains also exhibited antifungal activity against F. keratoplasticum and/or the human-pathogenic yeast Candida albicans (72.7%). Mass spectral network analyses of active extracts from bacterial isolates and egg clutches revealed compounds that may be involved in preventing microbial overgrowth. Several secondary metabolites were identified from ANG/JC bacteria and egg clutches, including the known antimicrobial lincomycin as well as a suite of glycerophosphocholines and mycinamicin-like compounds. These results shed light on a widely distributed but poorly understood symbiosis in cephalopods and offer a new source for exploring bacterial secondary metabolites with antimicrobial activity.

Seasonality and temporal correlation between community antibiotic use and resistance in the United States

BACKGROUND

Therapeutic antibiotic use in humans is a significant driver of antibiotic resistance. The seasonal effect of antibiotic use on antibiotic resistance has been poorly quantified because of lack of large-scale, spatially disaggregated time-series data on antibiotic use and resistance.

METHODS

We used time-series analysis (Box-Jenkins) on US antibiotic usage from IMS Health and on antibiotic resistance from The Surveillance Network from 1999-2007 to estimate the effect of aminopenicillin, fluoroquinolone, trimethoprim/sulfamethoxazole, and tetracycline usage on resistance of Escherichia coli to drugs within these classes. We also quantified the effect of fluoroquinolone and macrolide/lincosamide usage on resistance of methicillin-resistant Staphylococcus aureus (MRSA) to ciprofloxacin and clindamycin (which has a similar mode of action to macrolides), respectively.

RESULTS

Prevalence of resistant Escherichia coli was significantly correlated with lagged (by 1 month) antibiotic prescriptions for aminopenicillins (0.22, P = .03) and fluoroquinolones (0.24, P = .02), which are highly prescribed, but was uncorrelated to antibiotic classes with lower prescription levels. Fluoroquinolone prescriptions were also significantly correlated with a 1-month lag with the prevalence of ciprofloxacin-resistant MRSA (0.23, P = .03).

CONCLUSIONS

Large-scale usage of antibiotics can generate seasonal patterns of resistance that fluctuate on a short time scale with changes in antibiotic retail sales, suggesting that use of antibiotics in the winter could have a significant effect on resistance. In addition, the strong correlation between community use of antibiotics and resistance isolated in the hospital indicates that restrictions imposed at the hospital level are unlikely to be effective unless coordinated with campaigns to reduce unnecessary antibiotic use at the community level.

Use of pristinamycin for infections by gram-positive bacteria: clinical experience at an Australian hospital

Thirty-six patients were treated with pristinamycin for 46 different microbiological isolates between April 2007 and July 2009. Pathogens included 9 methicillin-resistant Staphylococcus aureus isolates, 13 methicillin-resistant coagulase negative staphylococci, and 9 vancomycin-resistant enterococci. Sites of infections included 12 osteomyelitis cases, 10 prosthetic joints, 4 other prostheses, and 1 epidural abscess. Five patients ceased treatment due to side effects. Ten patients were cured of their infections, and 21 patients had infections successfully suppressed.

Occurrence of macrolide-lincosamide-streptogramin resistances among staphylococcal clinical isolates at a university medical center. Is false susceptibility to new macrolides and clindamycin a contemporary clinical and in vitro testing problem?

A total of 2189 staphylococcal strains at the University of Iowa Hospitals and Clinics (Iowa City, IA) were initially screened to determine the incidence of constitutive (29.8%) and potential inducible macrolide-lincosamide-streptogramin (MLS) resistance (11.3%). Staphylococcus haemolyticus and S. epidermidis (62.5% and 55.3%) showed the highest incidence of constitutive resistance. Staphylococcus hominis had the highest incidence of inducible resistance (40.6%), while S. aureus had the lowest rate for both resistance types. The overall ratio of constitutive-inducible MLS resistance was 4:1. Among strains initially speciated using the Vitek System GPI card, there was only a 69% species identification reproducibility, and 78% accuracy versus a reference identification method. A random sample of 105 Staphylococcus spp. isolates with discordant macrolide (erythromycin resistant) and lincosamide (clindamycin susceptible) susceptibility patterns were tested against 16 antimicrobial agents by using a reference broth microdilution method. All erythromycin-resistant Staphylococcus spp. were also resistant to other 14-member macrolides and azithromycin, while all organisms remained susceptible to clindamycin, rifampin, vancomycin, and the streptogramin compounds (RP59500 and virginiamycin). Resistance to teicoplanin was identified among some oxacillin-resistant S. haemolyticus strains. Of 105 isolates, 65 (62%) showed inducible MLS resistance, 28 (27%) were noninducible, and 12 (11%) were either fully susceptible or resistant to the MLS drugs (Vitek System interpretation errors). MLS disk induction tests revealed two inducible resistance phenotypes: ML and MLS. Staphylococcus aureus showed the highest inducible resistance rate at 95% with an MLS-predominant pattern. In contrast, endemic S. haemolyticus isolates did not demonstrate inducible resistance that is, efflux-mediated erythromycin resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Macrolide-lincosamide-streptogramin resistance patterns in Clostridium perfringens from animals

Different patterns of resistance against commonly used macrolide, lincosamide, and streptogramin antibiotics were found in Clostridium perfringens of animal origin. The patterns were designated as (i) macrolide-lincosamide-streptogramin group B generalized resistance, (ii) macrolide-lincosamide generalized resistance, (iii) macrolide-lincosamide inducible resistance, and (iv) macrolide-lincosamide-streptogramin low-level generalized resistance. The strains of the fourth pattern were able to inactivate pristinamycin and virginiamycin. The macrolide-susceptible strains showed a bimodal distribution of lincomycin and clindamycin susceptibility levels. The susceptible strains were inhibited by 0.25 micrograms of lincomycin per ml and 0.03 micrograms of clindamycin per ml. The low-level resistant strains were inhibited at concentrations of 2 to 4 micrograms of lincomycin per ml and 0.5 to 2 micrograms of clindamycin per ml.

Antibiotics of the virginiamycin family, inhibitors which contain synergistic components

Images

Bacteroides fragilis resistant to the administration of clindamycin

The susceptibility of Bacteroides fragilis to the administration of clindamycin, and the efficacy of this agent in Bacteroides infections are well documented. Clindamycin-resistant strains of B. fragilis were isolated from two patients with bacteremia at two institutions. Clinically significant resistance to clindamycin therapy has not been noted previously in B. fragilis infections.

Chelocardin-inducible resistance in Escherichia coli bearing R plasmids

Two plasmid-linked tetracycline resistance characters, tet A and tet B, were distinguishable in part, according to the level of resistance they conferred to minocycline (<3 mug/ml for tet A; >6 mug/ml for tet B). Escherichia coli K-12 strains that harbored the tet B character were also resistant to tetracycline but susceptible to chelocardin. In such tet B strains, subinhibitory concentrations of tetracycline could induce resistance to chelocardin as well as to otherwise inhibitory concentrations of tetracyclines. Chelocardin itself was ineffective as an inducer and therefore could be used to select constitutively resistant mutants. E. coli K-12 strains harboring the tet A character were also resistant to tetracycline and susceptible to chelocardin; tetracycline did not induce resistance to chelocardin in these strains.

In vitro development of resistance to erythromycin, other macrolide antibiotics, and lincomycin in Mycoplasma pneumoniae

Mycoplasma pneumoniae was made highly resistant to erythromycin in vitro by serial subculture in broth media containing erythromycin. The resistance developed to erythromycin was 200 mug/ml with the Mac strain, a prototype of M. pneumoniae, and 10 mug/ml with the Fukumura strain, an isolate. The erythromycin resistance was accompanied by cross resistance to other macrolide antibiotics (leucomycin, josamycin, spiramycin, and oleandomycin) and to lincomycin, but there was no resistance to vernamycin B. Resistance to the antibiotics developed in vitro or in vivo was stable after the microorganisms were repeatedly transferred in antibiotic-free media.

In-vitro comparison of erythromycin, lincomycin, and clindamycin

The in-vitro antibacterial activities of erythromycin, lincomycin, and clindamycin, a new derivative of lincomycin, were compared. Clindamycin was always more active than lincomycin, and was either as active as erythromycin or more so against betahaemolytic streptococci, Streptococcus viridans, Str. pneumoniae, and erythromycin-sensitive Staphylococcus aureus. It was also fully active against most erythromycin-resistant strains of Staph. aureus. On the other hand, it was somewhat less active than erythromycin against Haemophilus influenzae and considerably less active than erythromycin against Str. faecalis and Neisseria gonorrhoeae.Clinical trials seem to be justified in infections with sensitive organisms for which erythromycin might have been indicated.

Erythromycin-inducible resistance in Staphylococcus aureus: survey of antibiotic classes involved

Certain erythromycin-resistant strains of Staphylococcus aureus remain sensitive to other macrolide antibiotics. If these strains are exposed to low levels of erythromycin, resistance to other antibiotics is induced. The antibiotics to which resistance is induced by erythromycin include: other macrolides as well as lincosaminide, streptogramin (group B) antibiotics but not chloramphenicol, amicetin, streptogramin (group A) antibiotics, tetracyclines, and aminoglycosides. Hence erythromycin induces resistance exclusively towards inhibitors of 50S ribosomal subunit function and, thus far, only with respect to three of six known classes of inhibitors which act on this subunit. In the four strains tested, erythromycin did not induce resistance to pactamycin or bottromycin, to fusidic acid (which inhibits a function involving both subunits), or to other antibiotics which do not inhibit ribosomal function. Thus, by inducing resistance erythromycin could antagonize the action of other antibiotics, and a consistent pattern of antagonism was observed to each antibiotic class in all of the strains in which this could be tested, as well as to other antibiotic members of the same chemical class in each bacterial strain.

Drug Antagonism between Lincomycin and Erythromycin

An antagonistic action can be demonstrated between lincomycin, a new antibiotic, and erythromycin, when the two drugs are allowed to diffuse into the same area of an agar plate seeded with a strain of Staphylococcus which is resistant to erythromycin but sensitive to lincomycin. The increase in the minimum inhibitory concentrations of lincomycin in the presence of erythromycin may be significant in clinical application. The antagonism does not depend on a reaction between the two antibiotics, but appears to be the result of an altered metabolism stimulated by erythromycin on erythromycin-resistant staphylococci.

LINCOMYCIN: A NEW ANTIBIOTIC ACTIVE AGAINST STAPHYLOCOCCI AND OTHER GRAM-POSITIVE COCCI: CLINICAL AND LABORATORY STUDIES

Preliminary results suggest that the antibiotic lincomycin (a product of Streptomyces lincolnensis var. lincolnensis) possesses certain valuable properties which include good in vitro activity against many strains of hospital staphylococci resistant to many other antibiotics. During a study of this agent, a selected series of severe staphylococcal infections due to resistant organisms were treated with lincomycin, with encouraging responses. Favourable results were also noted in seven cases of osteomyelitis. Lincomycin may be administered by the oral or parenteral routes to adults and infants and satisfactory serum blood levels obtained. So far as the authors' limited experience enables them to conclude, and at the dose range tested, this antibiotic promises to be one of low toxicity.