[Antibacterial therapy of acute sinusitis in outpatient practice: results of a multicenter trial]

Now there is no generally accepted practice of antibacterial therapy of acute sinusitis in outpatient clinics of Russia. Choice of antibacterial drugs is often made without consideration of the most probable causative agents of the infection. Out-of-date antibiotics used in many cases do not satisfy modern requirements. Clinically essential features of pharmacokinetics are in some cases ignored. Parenteral administration is often unjustified, combined antibiotic treatment is not always validated.

[Current antibacterial therapy of acute otitis media]

General approaches to general and local therapy of acute otitis media are validated and schemes of antibacterial treatment of this disease are proposed.

[Pre- and intraoperative preparation of patients with pyoinflammatory diseases of the ear, pharynx and paranasal sinuses]

The authors consider the problems of effective general and local antibiotic therapy regarding most frequently occurring now causative agents and doses of antibacterial drugs. Combined use of antibacterial drugs and immunostimulators is analysed as antibacterial drugs deteriorate nonspecific immunity.

[Dynamic study of antibiotic resistance of bacterial environment of the ENT department]

A dynamic 4-year monitoring of aerobic bacterial environment in the ENT department shows its relative qualitative stability with predominance of the coccal flora, primarily staphylococcal. Gram-negative flora was represented for the most part with non-fermentating microorganisms, most of them Acinetobacter. A wide-spectrum resistance to antibacterial drugs was found. This resistance has a trend to extend.

Antimicrobial use in paediatric wards of teaching hospitals in Bangladesh

To ascertain the pattern of antimicrobial use and to assess its appropriateness a 4-month prospective study was conducted from January through April 1998 in paediatric wards of five selected medical college hospitals in Bangladesh. The hospitals were selected by simple random technique. Every patient in the paediatric wards of the selected hospitals who was being treated with antimicrobials during the data collection period was considered for the study. The treatment charts of 2171 admitted paediatric patients were reviewed. Pneumonia and diarrhoea were the two most common infectious diseases among them. The most commonly used antimicrobials were ampicillin, gentamicin, amoxicillin, cloxacillin and ceftriaxone. The majority of the admitted paediatric patients (56.1%) included in this study received two or more antimicrobials in combination for their treatment. The percentages of appropriate antimicrobial treatment of pneumonia, and diarrhoea were 57.1% and 67.8% respectively across the hospitals. The evident of high percentages of inappropriate antimicrobial treatment for the most common infectious diseases suggested the need for intervention to improve antimicrobial use in hospitals.

Diversidad clonal y sensibilidad a los antimicrobianos de Acinetobacter baumannii aislados en hospitales españoles. Estudio multicéntrico nacional: proyecto GEIH-Ab 2000

INTRODUCTION

A nationwide multicenter study was performed in Spain to evaluate the clonal diversity and antimicrobial susceptibility of Acinetobacter baumannii clinical isolates.

METHODS

A total of 221 consecutive A. baumannii isolates recovered from clinical samples from 25 Spanish hospitals during November 2000 were studied. Isolate identification was performed by phenotyping methods and by amplified rDNA restriction analysis. Clonal relationships among A. baumannii isolates were determined by pulsed field gel electrophoresis. MICs of amikacin (AK), ampicillin (AP), cephalothin (CF), cefoxitin (FX), ceftazidime (CZ), ciprofloxacin (CP), cotrimoxazole (T/S), doxycycline (DX), gemifloxacin (GX), gentamicin (GN), imipenem (IP), meropenem (MP), minocycline (MI), piperacillin (PP), polymyxin B (PB), rifampicin (RI), tetracycline (TT), sulbactam (SB) and tobramycin (TO) were determined by microdilution (NCCLS guidelines).

RESULTS

Seventy-nine A. baumannii clones were differentiated. MIC50/MIC90 (mg/L) values for the 221 A. baumannii isolates were PP: > 512/> 512; AP, CF, FX: > 256/> 256; TT, GN: > 128/> 128; CZ: 128/> 256; CP: > 64/> 64; FP: 64/256; AK: 32/256; DX: 32/64; GX: > 16/> 16; TO: 16/128; SB, T/S: 16/64; MP: 8/> 128; IP: 4/128; RF: 4/8; MI: 2/16 and PB: 1/2. Percentages of susceptible isolates were PB: 100%; MI: 65.8%; IP: 52.5%, RF: 49.3%; SB: 46.7%; MP: 43.1%; AK: 34.7%; DX: 32.0%; TO: 21.3% and CZ, FP, GN, T/S, TT, GX, CP, AP, PP, CF and FX: < 20%.

CONCLUSIONS

A. baumannii isolates show high clonal variability in Spain. The most active antimicrobial agents against this organism were polymyxin B, minocycline, rifampicin, imipenem, sulbactam, meropenem, amikacin and doxycycline.

Antibiotic use and preterm labor: attitudes and practice patterns of North Carolina obstetric providers

BACKGROUND

Despite the reported link between subclinical genital tract infection (GTI) and preterm labor (PTL), it is not certain that treating PTL empirically with antibiotics decreases neonatal morbidity and mortality. This study describes the beliefs of family physicians and nurse-midwives regarding the link between subclinical GTI and PTL and their use of empiric antibiotics to treat spontaneous PTL.

METHODS

This was a survey of family physicians, family practice residents, and midwives (n = 588) who practice obstetrics in North Carolina. The response rate was 61%.

RESULTS

Ninety-six percent of providers search for GTI, and 76% believe antibiotics for presumed infection will benefit the neonate. Wide variation in the use of antibiotics exists within groups and between groups of providers. Nurse-midwives are more likely than family physicians to use broad-spectrum antibiotics (p < 0.001).

CONCLUSIONS

Family physicians and nurse-midwives are uncertain about the optimal management of PTL. Empiric antibiotic use varies widely despite the lack of supportive data.

Degradation of antimicrobial histatin-variant peptides in Staphylococcus aureus and Streptococcus mutans

Histidine-free variants of salivary histatin 5 have a broad antimicrobial activity against various bacteria. In relation to a possible therapeutic application, we were interested in the susceptibility of these small peptides (14 amino acids long) to microbial proteinases and whether this affects their antimicrobial activity. Analyses by SDS-PAGE of supernatants of peptide-bacteria incubation showed a reduction in protein bands within 15 minutes' incubation, as a result of cellular internalization. Degradation products of dhvar1 and dhvar2 appeared within one hour in the supernatants of Streptococcus mutans and Staphylococcus aureus. In contrast, the variants dhvar3 and dhvar4 were more resistant to degradation under the same conditions. MALDI-TOF analyses identified cleavage of dhvar1 and dhvar2 at Glu(6). The N-terminal peptide part (1-6) of dhvar1 and 2 showed no bactericidal activity, while peptide fragment (7-14) showed a highly reduced bactericidal activity.

Evaluation of the Osiris expert system for identification of beta-lactam phenotypes in isolates of Pseudomonas aeruginosa

Osiris is a video zone size reader for disk diffusion tests featuring a built-in extended expert system (EES). The efficacy of the EES for the identification of the beta-lactam susceptibility phenotypes of Pseudomonas aeruginosa isolates was evaluated. Thirteen beta-lactams were tested in four laboratories by the disk diffusion test with 53 strains with well-characterized resistance mechanisms, including the production of 12 extended-spectrum beta-lactamases (ESBLs). The plates were read with the Osiris system and the results were interpreted with the ESS, and then the phenotype identified by the EES was compared to the resistance mechanism. The strains were also screened for the presence of ESBL production by a double-disk synergy test by placing the strains between an extended-spectrum cephalosporin-containing disk and a clavulanic acid-containing disk at distances of 30, 20, 15, and 10 mm from each other. Overall, the EES accurately identified the phenotypes of 88.2% of the strains and indicated an association with several mechanisms for 3.8% of the strains. No phenotype was identified in four strains with low levels of penicillinase production. Misidentifications were observed for two penicillinase-producing strains: one strain with partially derepressed cephalosporinase production and one strain overexpressing the MexA-MexB-OprM efflux system. The production of only four ESBLs was detected by the standard synergy test with a 30-mm distance between the disks. The production of five further ESBLs was identified by reducing the distance to 20 mm, and the production of the last three ESBLs was detected only at a distance of 15 or 10 mm. Our results indicate that the Osiris EES is an effective tool for the identification of P. aeruginosa beta-lactam phenotypes. A specific double-disk synergy test with reduced disk distances is necessary for the detection of ESBL production by this organism.

Comparison and evaluation of Osiris and Sirscan 2000 antimicrobial susceptibility systems in the clinical microbiology laboratory

The Osiris and Sirscan 2000 systems are two semiautomated systems that can be used to read and interpret the results on disk diffusion agar plates. They are both used for determination of susceptibility to antimicrobial agents. The present study compared both systems versus the NCCLS standard method of visual reading with a ruler. Both inpatient and outpatient samples with a total of 315 nonfastidious gram-negative strains were obtained. In total, 3724 organism-antimicrobial agent combinations that fulfilled the NCCLS guidelines for disk diffusion susceptibility testing were evaluated prospectively. The results obtained with both systems in comparison with those obtained by the classical nonautomated means of interpretation were excellent, with correlation coefficients of 0.96 for both systems. The overall agreements for susceptibility interpretation were 96.56 and 96.24% with the Osiris and Sirscan systems, respectively. Very major errors were obtained for 8 (1.07%) and 10 (1.34%) organism-antimicrobial agent combinations with the Osiris and Sirscan systems, respectively. In addition, major errors were obtained for 2 (0.07%) and 6 (0.21%) combinations with the Osiris and Sirscan systems, respectively. Minor errors were obtained for 118 and 124 organism-antimicrobial agent combinations with the Osiris and Sirscan systems, respectively. Overall, both the Osiris system and the Sirscan system are comparable and reliable systems for determination of interpretative categories from the zone diameters of standard disk diffusion test plates.

Antimicrobial susceptibilities of salmonella strains isolated from humans, cattle, pigs, and chickens in the Netherlands from 1984 to 2001

We monitored antimicrobial susceptibility data for Salmonella strains isolated from humans, cattle, pigs, and chickens in The Netherlands from 1984 to 2001 in order to provide insight into the dynamics of resistance over time. The strains were tested for their susceptibilities to seven antimicrobial agents by the agar diffusion method. Resistance was most common in Salmonella enterica subsp. enterica serovar Typhimurium. Among the strains from humans, pigs, and chickens, it was found that the level of resistance of serovar Typhimurium strains to tetracycline, ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole increased from 1984 to 2001. This increase could be attributed to the emergence of multidrug-resistant serovar Typhimurium DT 104. Among the strains from cattle, it was found that the level of resistance of serovar Typhimurium strains, which was already very high in the 1980s, declined during the study period to the same levels as those for the strains from the other species from 1996 to 2001. Serovar Enteritidis isolates remained susceptible during the entire survey period. Among serovar Paratyphi B variation Java strains isolated from chickens, resistance to furazolidone, flumequine, trimethoprim-sulfamethoxazole, and ampicillin emerged, although furazolidone was not used after 1990. Together, the data indicate that the levels and patterns of resistance differed considerably between Salmonella serovars isolated from one host species.

Antibiotic use profile at paediatric clinics in two transitional countries

PURPOSE

In this study, we evaluated antibiotic utilisation pattern at two paediatric clinics in different European (transitional) countries: Croatia (Rijeka) and Russia (Smolensk).

METHODS

Antibiotic utilisation during the year 2000 was observed using the ATC/defined daily doses (DDD) methodology (ATC code-J01). Drug-usage data was expressed in numbers of DDD/100 bed-days and the DU90% profile.

RESULTS

In Rijeka, 35 different systemic antibiotics were used and in Smolensk 22. The overall consumption of antibiotic drugs in Rijeka was more than three times higher than in Smolensk (28.96 vs 8.3 DDD/100 bed-days). The top five antibiotic drugs used in Smolensk were amoxicillin, mydecamicin, ampicilin, doxycylin, gentamicin; and in Rijeka cefuroxime axetil, ceftriaxone, azytromycin, ceftibuten and amoxicillin.

CONCLUSION

Differences in antibiotic prescribing patterns are greater than expected. The pattern of antibiotic utilisation in both countries implies that regional control measures and guidelines for antibiotic use in children should be urgently established.

Hypersensitivity reactions to non-beta-lactam antibiotics

As alternatives to beta lactam antibiotics continue to be developed, an increasing number of patients are experiencing hypersensitivity reactions to these agents. Unfortunately, unlike penicillin, there are no validated skin testing reagents to aid in confirming the presence of specific IgE antibodies to these drugs. This review summarizes what is known about hypersensitivity reactions to non-beta lactam antibiotics, and includes practical approaches to readministering these drugs in selected situations. Sulfonamides, vancomycin, macrolides, tetracyclines, fluoroquinolones, and anti-virals are included in the discussion.

Treatment of community-acquired methicillin-resistant Staphylococcus aureus in children

PURPOSE OF REVIEW

The concept of methicillin-resistant Staphylococcus aureus (MRSA) associated with broad resistance, nosocomial acquisition, and known risk factors has recently been expanded. A new type of MRSA that is resistant to fewer antibiotics has emerged in pediatric practice since the mid-1990s. These isolates are community acquired and have been reported from diverse geographic regions. Awareness of these organisms is important for appropriate treatment of S. aureus infections in children.

RECENT FINDINGS

Community-acquired MRSA (CA-MRSA) isolates are similar in many respects to community-acquired methicillin-susceptible S. aureus (CA-MSSA). There are usually no differences in risk factors between children with CA-MRSA infections and those with CA-MSSA infections or their household contacts. In one study, however, multivariate analysis showed that age greater than 1 year and health care contact in the preceding month were significant risk factors for CA-MRSA. Skin and soft tissue infections are the most common manifestations, although serious invasive infections and death may occur. Pneumonia has been reported more often in children with CA-MRSA than in those with CA-MSSA. Clindamycin is an effective therapy for CA-MRSA, but there is a risk for development of clindamycin resistance during treatment of a CA-MRSA that is clindamycin susceptible and inducibly erythromycin resistant. Trimethoprim-sulfamethoxazole is likely to be effective, and linezolid is a new option for treatment.

SUMMARY

The appearance of CA-MRSA has important implications for therapy of infections caused by S. aureus in children. Three specific issues are the development of resistance during clindamycin therapy, insufficient data on the use of trimethoprim-sulfamethoxazole in serious CA-MRSA infections, and the appropriate role for newer antibiotics such as linezolid.

Vancomycin resistance: occurrence, mechanisms and strategies to combat it

Vancomycin has long been considered the antibiotic of last resort against serious and multi-drug-resistant infections caused by Gram-positive bacteria. However, vancomycin resistance has emerged, first in enterococci and, more recently, in Staphylococcus aureus. Here, the authors attempt to review the prevalence and the mechanisms of such resistance. Furthermore, they focus on strategies that have been developed or are under current investigation to overcome infections caused by vancomycin-resistant strains. Among these are glycopeptide derivatives with higher potency than vancomycin, small molecules that resensitise bacteria to the antibiotic and novel non-glycopeptide antibiotics. These agents are targeted to interfere with protein and/or peptidoglycan (PG) synthesis and integrity or with membrane permeability. Whilst most of these agents are still in clinical or preclinical development, some have entered the clinic and currently represent the only option for treating vancomycin-resistant enterococci (VRE).

[Usefulness of antibiotics in the treatment of bronchial asthma]

The efficacy and safety of antibiotics in the treatment of asthma are not unequivocal. Among various antibiotics, macrolides play the main role in the therapy of bronchial asthma. Macrolides are useful in the treatment of asthma not only because of their antimicrobial activity. The mechanism of action of macrolides in improving asthma and reducing airway responsiveness is evaluated especially due to their activity in non-infectious asthma. Macrolides may not only enhance the host defense system through increased cytokine synthesis, but also exhibit anti-inflammatory activity mediated by anti-inflammatory cytokines. The steroid-sparing effect of macrolide antibiotics has been postulated to contribute to their beneficial actions in the treatment of asthma. Macrolides may be useful in the treatment of patients with steroid-dependent asthma, probably because they inhibit eosinophilic inflammation. It has also been suggested that the effect of macrolides on bronchial hyperresponsiveness is mediated by their inhibitory action on superoxide production and chemotaxis of polymorphonuclear neutrophils and the mixed lymphocyte reactions. In spite of these suggestions, the mechanism of action of macrolides in asthmatic syndrome is not clear. Only well-designed and conducted clinical studies are capable of assessing the efficacy and safety of immunosuppressive macrolides in the treatment of asthma.

[Efficacy of some new antibiotics in treating experimental brucellosis]

Brucella pathogens are highly susceptible in vitro to pefloxacin, lomefloxacin, meropenem and azithromycin. High efficacy of these drugs was demonstrated for experimental brucellosis treatment, azithromycin being the most active. Meropenem and azithromycin implementation resulted in more rapid and full normalization of the bactericidial and energy systems of the experimental animals peripheral blood cells.

Synthesis and analysis of a methyl ether derivative of tetracycline which inhibits growth of Escherichia coli

Tetracycline is a widely used broad spectrum antibiotic. A derivative of tetracycline was synthesized by methylation (-CH3) of the phenolic hydroxyl group, with the use of diazomethane (CH2N2). A methyl ether group is then formed from the reaction with diazomethane, which replaces the hydroxyl group. The newly formed derivative has reduced hydrogen bonding capability relative to the unmodified tetracycline. An infrared spectra shows the appearance of the ether group on the derivative and the Log P calculations indicate that the derivative has increased lipophilic tendency. The Lipophilic Substituent Constant calculated for the tetracycline derivative is 0.46, indicating a lipophilic substituent. The tetracycline derivative was soluble in aqueous solvents and was stable for more than five weeks when stored at < or = 0 degrees C. The derivative was placed in tissue culture utilizing Luria-Bertani (LB) media, at a concentration of 12.0 microg/mL and inhibited the growth of E. coli (XL-1 blue) from 15% to 20% within the initial sixteen hours.

Antibiotics

The chapter informs about different types of antibiotics, their structure, biosynthesis and their regulation. Industrial cultivation and isolation of antibiotics is described in the chapter. Search for microorganisms producing antibiotics and preparation of high-producing strains is described. Resistance against antibiotics in producing microorganisms and pathogens is discussed.