Antibiotic sensitivity of pneumonia pathogens in newborns and problems of antibacterial therapy of the pathologic process]

The results of the bacteriological investigation of the secretion from the trachea, large bronchi and fauces of 36 newborns (including 27 preterms) with severe pneumonia were analyzed. 20 of them were born of women with complicating somatic, obstetric and gynecologic histories: candidiasis, herpes genitalis, chronic endometritis, adnexitis or chronic pyelonephritis that could be the risk of the fetus intranatal infection. During the acute period of pneumonia in the newborns within the first 4-8 days of life mainly Pseudomonas aeruginosa was isolated (51.3 per cent), Staphylococcus epidermidis, S. haemolyticus and Enterococcus faecalis were less frequent (18.9, 8.1 and 5.4 per cent, respectively). Klebsiella pneumoniae, Streptococcus anhaemolyticus and other organisms were extremely rare. On the whole the gramnegative microflora predominated. The study of the antibiotic susceptibility showed that the majority of the P. aeruginosa isolates were susceptible to amikacin and polymyxin B, the isolates susceptible to ceftazidime were less frequent, 20-25 per cent of the isolates were susceptible to ciprofloxacin, cefoperazone and imipenem and practically no isolates were susceptible to gentamicin. The S.epidermidis isolates were susceptible to rifampicin and vancomycin and in rare cases to fusidin and amikacin and resistant to oxacillin. When the treatment course was more than 15 days, the isolates proved to be susceptible to 1/3 of the presently available antibiotics. Because of the host low protective forces, peculiarities of the infection pathways and high frequency of the resistant strains it is valid to include netilmicin, imipenem, cefoperazone and ceftriaxone to the complex therapy of the newborns along with the substitution immunotherapy.     

Susceptibility of Arcobacter butzleri isolates to 23 antimicrobial agents

AIMS: The objective of this study was to determine the susceptibility of Arcobacter butzleri isolates to various antimicrobial agents used in the treatment of infectious diseases in humans and animals. METHODS AND RESULTS: Thirty-nine A. butzleri strains isolated from broiler chickens were tested for their susceptibility to 23 antimicrobial agents using a disc diffusion method. All isolates were resistant to aztreonam, cefuroxime sodium, cephalothin, orbenin, oxacillin, penicillin G and trimethoprim/sulphamethoxazol. Of the 39 isolates tested, 26 were also found resistant to amoxycillin, amoxycillin/clavulanic acid and ampicillin. One isolate was resistant to, and four showed intermediate level of resistance to, erythromycin. All isolates were susceptible to amikacin, chloramphenicol, danofloxacin, enrofloxacin, nitrofurantoin, nalidixic acid, tetracyclines and tobramycin. CONCLUSIONS: The majority of the isolates were found resistant to antibiotics commonly used for the treatment of infectious bacterial diseases in humans and animals. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that A. butzleri strains vary in their resistance to certain kinds of antibiotics and caution should be taken when choosing a suitable antibiotic for the treatment of disease(s) caused by this organism.     

Occurrence and antibiotic sensitivity of Enterobacteriaceae isolated from a group of Jordanian patients with community acquired urinary tract infections

The type and antibiotic sensitivity of urinary tract pathogens may differ in various communities. Of 207 isolates recovered from midstream urine specimens collected from a group of patients with community acquired urinary tract infections (UTI), 86% were species of Enterobacteriaceae. The most frequently recovered pathogens were Escherichia coli (82%), Klebsiella spp. (7.3%), Proteus spp. (6.2%), Enterobacter spp. (3.4%) and Citrobacter spp. (1.1%). High rates of resistance were found against ampicillin (95%), tetracycline (86%), carbenicillin (84%), trimethoprim/sulphamethoxazole (48%), and amoxycillin/clavulanic acid (45%). For the antibiotics tobramycin, aztreonam, ceftriaxone and gentamicin 7% of the isolates were resistant, while resistance varied from 9-18% for amikacin, ciprofloxacin, norfloxacin, nalidixic acid and cefuroxime. The incidence of UTI caused by Enterobacteriaceae was three times higher in females than in males, particularly in young and middle age groups (< or = 19 and 20-39 years).     

Klebsiella, Enterobacter, and Serratia: Biochemical Differentiation and Susceptibility to Ampicillin and Three Cephalosporin Derivatives

Three hundred twenty-nine strains of the tribe Klebsielleae were compared by several biochemical tests and by susceptibility to selected antibiotics. Biochemical tests included urease, amino acid decarboxylase, and hydrogen sulfide production; fermentation of lactose and dextrose; motility; and tests in the IMViC (indole, methyl red, Voges-Proskauer, citrate) series. The isolates were: Klebsiella species, 67.5%; Enterobacter species, 28%, and Serratia species, 4.5%. Minimal inhibitory concentrations of cephaloridine, cephalothin, and a new cephalosporin, cephalexin, and of ampicillin were determined by the agar dilution procedure. Cephalosporins at 20 mug/ml or less inhibited 90% of the Klebsiella strains but only 15% of the Enterobacter strains. Ampicillin inhibited 27% of Enterobacter strains and 17% of Klebsiella strains. Serratia isolates were insensitive to the cephalosporins and ampicillin. The results suggest that precise identification of this group to the generic level can be accomplished readily in the clinical laboratory and that such information is helpful in the preliminary selection of an antibiotic for treatment of clinical infections.     

Periodontal disease as reservoir for multi-resistant and hydrolytic enterobacterial species

AIMS: This investigation aimed to isolate enteric rods from subgingival sites of patients presenting chronic periodontitis lesions, and to assess antimicrobial resistance and expression of hydrolytic enzymes. METHODS AND RESULTS: Enterobacteriaceae were isolated from 20% patients, and assayed for antimicrobial susceptibility and hydrolytic enzymes with specificity to different substrates. Isolates comprised seven Enterobacter cloacae (43.75%), five Serratia marcescens (31.25%), one Klebsiella pneumoniae (6.25%), one Enterobacter aerogenes (6.25%), one Pantoea agglomerans (6.25%), and one Citrobacter freundii (6.25%). Gelatinase activity was observed for 75% strains; caseinase and elastase was produced by six and two strains, respectively. DNase, lecithinase and lipase were expressed by S. marcescens. Most of strains were resistant to ampicillin (93.75%) and amoxicillin/clavulanic acid (81.25%). The majority of strains were susceptible to cephalosporins and aztreonam. Enterobacteria remained susceptible to imipenem, streptomycin and fluoroquinolones. Resistance to gentamicin, amikacin, sulfamethoxazole/thrimethoprim, tetracycline, and chloramphenicol were also observed. Eight strains presented multiple drug resistance. CONCLUSIONS: Subgingival sites from periodontal diseases contain multi-resistant and hydrolytic enzyme-producing enterobacteria that may contribute to overall tissue destruction and spreading. SIGNIFICANCE AND IMPACT OF THE STUDY: Enterobacteria isolated from patients generally considered as healthy individuals poses periodontal diseases as reservoir for systemic infections particularly in immunocompromised and hospitalized hosts.     

Sensitivity of Shigella to antibiotics]

Three hundred and twenty two Shigella cultures isolated from dysentery patients within 1986-1989 were tested with the use of standard paper disks for their sensitivity to levomycetin, streptomycin, tetracycline, monomycin, neomycin, kanamycin, erythromycin, gentamicin, carbenicillin, ampicillin, oxacillin, methicillin and doxycycline. The number of the cultures belonging to Shigella sonnei amounted to 85.1 per cent of the total number of the strains studied. 91.9, 89.5, 87.3, 87.3, 80.1 and 80.1 per cent of the cultures were sensitive to gentamicin, kanamycin, carbenicillin, neomycin, levomycetin and ampicillin, respectively. 99.4 per cent of the isolates were resistant to streptomycin and 97.2 per cent were resistant to tetracycline. The sensitivity to erythromycin remained rather high (70.2 per cent). The overwhelming majority of the Shigella sonnei isolates had multiple resistance.     

Antimicrobial resistance in Gram-negative bacilli isolated from infant formulas

A total of 90 samples of infant formula (IF) were collected from the lactary of a teaching hospital, during a 4-month period from July to August 1999. The sanitary conditions of the formulas were analyzed, and a physiological characterization of Gram-negative bacillus isolates and antimicrobial susceptibility testing were performed. Colony counts were considered to be unacceptable for the majority of the IF samples and the contamination rates were related to inadequate handling. Coliforms (35 degrees C and 45 degrees C growth) were detected in most of the IF tested. Klebsiella pneumoniae, Citrobacter freundii, Cedacea davisae, Klebsiella planticola and Enterobacter cloacae were the isolates most commonly identified. Antimicrobial susceptibility testing showed significant resistance rates, particularly to amoxicillin/clavulanic acid, cefoxitin, cephalotin or ampicillin. One extended-spectrum beta-lactamase-producing K. pneumoniae strain was also recovered.     

Antimicrobial susceptibility, β-lactamase and enterotoxin production in <Emphasis Type="Italic">Bacillus cereus</Emphasis> isolates from clinical and food samples

The antimicrobial susceptibility of 30 clinical and 30 food Bacillus cereus isolates was determined. All isolates were susceptible to streptomycin, ciprofloxacin and gentamicin, 90 % of them to clindamycin and vancomycin, and 67 % to erythromycin. All isolates were resistant to amoxicillin with clavulanic acid, ampicillin, cefotaxime, ciprofloxacin, cloxacillin, cefotaxime with clavulanic acid and penicillin. The MIC values (determined by E-tests) were 48–256 mg/L for ampicillin, 0.19–1.5 mg/L for gentamicin, 0.125–1.0 mg/L for clindamycin, 0.047–4.0 mg/L for erythromycin and 1.5–16 mg/L for vancomycin. The MICs 4.6–18.75 g/L were observed for penicillin using the microdilution method. The presence of metallo-β-lactamases was detected by E-test for 100 % of strains. Nonhemolytic diarrheal enterotoxin (NHE) was produced by 98.3 % of strains, while 31.7 % of them produced hemolytic diarrheal enterotoxin (HBL). Clinical isolates produced 10 % more HBL than food isolates. The psychrotrophic strains isolated from food samples produced NHE at 6.5 °C in 73 % of cases.     

Antibiotic resistance of staphylococci isolated from outpatients

The aim of the study was to determine susceptibility of 587 strains of S. aureus and 85 strains of coagulase-negative staphylococci isolated from outpatients in Poznań to co-trimoxazole, amoxycillin/clavulanic acid, erythromycin, gentamycin, doxycycline, ampicillin, oxacillin, cephradine, clindamycin and neomycin. Also methicillin-resistant strains were determined as well as strains ability to produce beta-lactamases. Susceptibility testing and examination of methicillin-resistant strains were performed by the disc diffusion techniques according to recommendation of NCCLS. Methicillin-resistant strains were additionally examined to their sensitivity to vankomycin and teicoplanin. beta-lactamase production was detected using nitrocefin impregnated discs and iodometric method. Amoxacillin/clavulanic acid, gentamycin, co-trimoxazole, cephradin, oxacillin and clindamycin occurred to be very active against both, S. aureus and coagulase-negative staphylococci. 84.7% to 100% of examined strains were sensitive to these drugs. Doxycyclin, erythromycin and ampicillin were less effective. Nine strains (1.5%) of 587 strains of S. aureus as well as 7 strains (8.7%) of coagulase-negative staphylococci were methicillin-resistant. All of methicillin-resistant strains were sensitive to vancomycin and teicoplanin. More than 75% of S. aureus and close to 50% of coagulase-negative staphylococci were able to produce beta-lactamases.     

Enterobacterial sensitivity to beta-lactam antibiotics]

The susceptibility to betalactams of 868 enteric bacteria isolated from the patients at the hospital was studied. The isolated pathogens included: E. coli (549), Klebsiella sp. (195), Serratia sp. (124). Ampicillin and cefazoline demonstrated the lowest activity. Cefotaxime, ceftazidime and imipenem were active against 90 per cent of isolates. Among E. coli isolates the susceptibility to the above mentioned drugs was the following: 95.1, 96.9, 99.3 per cent, among Klebsiella sp.--89.7, 88.7, 97.9 per cent, among Proteus sp.--89.5, 90.3, 91.9 per cent respectively. Thus cefotaxime may be used in antibacterial empiric therapy if Pseudomonas aeruginosa infection is excluded.     

Prevalence and antimicrobial susceptibility of staphylococci isolated from the skin surface of clinically normal cats

Samples were collected from 148 adult cats, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, amoxycillin, ampicillin, cephalexin and rifampin. Methicillin resistance was also determined. Ninety-eight isolates were obtained (66% of samples). Coagulase-negative species were most common, and the most frequently isolated species (37 samples) was Staph. felis . Other coagulasenegative species, such as Staph. simulans , Staph. epidermidis and Staph. Saprophyticus were also isolated. Coagulase-positive species were obtained from 40 cats; the most frequent was Staph. intermedius (26 samples), followed by Staph. aureus (14 samples). Resistance to antibiotics was frequently observed, with 58·2% of the isolates showing resistance to at least one drug. Resistance to Penicillin G was observed in 49 of the 98 isolates (50%), 22 samples were resistant to oxacillin (22·4%) and 12 to rifampin (12·2%). Resistance to amoxycillin and ampicillin was very similar to that observed to Penicillin G. Gentamicin was the most active antimicrobial agent. Three MRSA (methicillin-resistant Staphylococcus aureus ) were isolated, which represents 21·4% of the isolates of that species. Nineteen MRS (methicillin resistant staphylococci) were also observed, distributed among Staph. intermedius (eight), Staph. simulans (six) and Staph. felis (five) isolates. The role of these micro-organisms on the skin of cats is discussed.     

Sensitivity of Corynebacterium diphtheriae isolated in Saint-Petersburg to antibacterial drugs]

One hundred and thirty strains of Corynebacterium diphtheriae isolated in St. Petersburg (42 toxigenic and 88 nontoxigenic) were tested with the method of serial dilutions in solid media for their susceptibility to 20 antibacterial drugs. The MICs of the drugs for the isolates ranged from < or = 0.015 to > or = 32.0 micrograms/ml. 13 per cent of the isolates was resistant at least to one antibacterial drug. The isolates resistant to erythromycin (11.5 per cent), lincomycin (11.5 per cent) and trimethoprim (8.5 per cent) were most frequent. 3 isolates (2.3 per cent) had multiple resistance to 8 drugs: benzylpenicillin, ampicillin, oxacillin, chloramphenicol, erythromycin, lincomycin, trimethoprim, and nitroxolin. No significant differences in the susceptibility of the toxigenic and nontoxigenic strains of C. diphtheriae were detected. Gentamicin, rifampicin, tetracycline, doxycycline and pefloxacin were the most active antibiotics.     

Amikacin resistance of clinical strains of Enterobacteriaceae and Pseudomonas]

Amikacin resistance was studied in 380 bacterial strains of Enterobacter, Klebsiella, Serratia, Pseudomonas and E. coli isolated in clinics of the Moscow Region. It was shown that 69 isolates were resistant to amikacin. Plasmid DNA was detected in 10 amikacin resistant isolates. Three of them belonging to Klebsiella and 3 belonging to E. coli contained plasmids controlling resistance to amikacin. The plasmids isolated from the strains of Klebsiella determined as well resistance to kanamycin and streptomycin but did not control resistance to sisomicin, tobramycin and gentamicin while the plasmids isolated from the strains of E. coli determined resistance to amikacin, kanamycin, gentamicin, tobramycin and sisomicin.     

Antibiotic susceptibility, serum response and surface properties of Klebsiella species

Altogether 130 clinical isolates of five Klebsiella species (K. pneumoniae, K. planticola, K. oxytoca, K. ornithinolytica and K. terrigena) were characterized, for their susceptibility to five antibiotics, for susceptibility to serum bactericidal activity and for their hydrophobic properties. All strains exhibited ampicillin resistance. Ampicillin/sulbactam, gentamicin and ofloxacin showed effectiveness in 63.1, 67.7 and 71.5% of the Klebsiella isolates. K. planticola manifested the highest level of resistance to these antibiotics. The majority of Klebsiella strains (93.9%) were susceptible to cefuroxime. Sixty-four strains (49.2%) were serum resistant and intermediate serum sensitivity was shown by 57 strains (43.8%). A high percentage of serum resistant strains (65%) was found in K. planticola. Moderately hydrophobic properties determined by adherence of bacteria to xylene were demonstrated in 25 strains (19.2%).     

Antimicrobial Susceptibility and rRNA Gene Restriction Patterns among Staphylococcus intermedins from Healthy Dogs and from Dogs Suffering from Pyoderma or Otitis Externa

A total of 60 Staphylococcus intermedins strains from dogs were investigated by their sensitivity to various antibiotics (50 strains) and by their rRNA gene restriction patterns (ribotyping) (60 strains). Fifteen isolates were from healthy dogs, 9 with otitis externa, and 36 with pyoderma, including 10 strains from a previous study. Sixty per cent of the 50 strains tested for antibiotic susceptibility demonstrated resistance to penicillin, 24% to spiramycin, 20% to tetracycline, 16% to chloramphenicol, and 2% to fucidic acid. All isolates were susceptible to amoxycillin with clavulanic acid, enrofloxacin, and sulphonamides with trimethoprim. There were no significant differences in antimicrobial susceptibility patterns observed among isolates from pyoderma, otitis externa or healthy dogs. Among the 60 strains studied by ribotyping, 10 different ribotypes were identified: 6 different ribotypes among isolates from otitis externa, 8 among isolates from pyoderma, and 5 among isolates from healthy dogs. One ribotype (profile C) was dominant among the isolates from healthy dogs while another ribotype (profile A) was dominant among strains from dogs suffering from pyoderma. This profile was not demonstrated in any of the strains from healthy dogs. From 5 different dogs suffering from pyoderma, 2 different clones were demonstrated based on their plasmid profile and antibiogram. In these dogs 1 of the clones always belonged to ribotype A. The results concerning strains of S. intermedins isolated from furunculosis suggest the existence of distinct subpopulations with different pathogenicity to dogs.     

Monitoring of uropathogens and their susceptibility to antibiotics]

Samples of urine collected from patients with complicated urology infection and hospitalized to the Moscow Region Research Clinical Institute in 1986, 1991, 1995 and 1999 were analysed. Of 11,444 samples examined, bacteriuria was estimated in 7143 samples. 9786 strains (29 genus) of bacteria were isolated--56.9 per cent as mono culture and 43.1 per cent as associations. Susceptibility to 21 antibiotic was determined by disk diffusion method for 1607 strains; beta-lactamase production was determined in 198 strains, MIC was determined for 41 antibiotics. Gram-negative rods relative amount among pathogens decreased substantially (84.7 per cent in 1986 against 61.6 per cent in 1999), particularly Enterobacteriaceae (74.7 per cent in 1986 against 41.4 per cent in 1999). Nonfermenting Gram-negative rods (NFGNR) relative amount increased (10.8 per cent against 19.2 per cent), along with Gram-positive cocci (19.8 per cent against 64.2 per cent), particularly coagulasenegative staphylococci (CNS) (10.8 per cent against 35.9 per cent) and enterococci (5 per cent against 16.5 per cent) and candida and fungi (0.5 per cent in 1986 against 15.9 per cent in 1999). At the period 1986-1999 the main pathogens in urology infection were E. coli, Enterobacter spp., NFGNR (including P. aeruginosa), Staphylococcus, CNS, Enterococcus spp. The problem pathogens for urological department were the following: E. coli, Klebsiella spp., Enterobacter spp., Proteus spp., NFGNR including P. aeruginosa, CNS, Enterococcus spp., candida and fungi. At the period 1991-1997 Gram-negative pathogens susceptibility to amikacin, ofloxacin, ciprofloxacin, imipenem, ceftazidime, cefotaxime was not changed in general, Gram-positive cocci (staphylococci and enterococci) retained the same susceptibility to vancomicin, cefamandol and amoxyclave. Staphylococci were also susceptible to amikacin, imipenem, rifampicin, oxacillin, ciprofloxacin, and ofloxacin. Production of beta-lactamase was registered for 38.7 per cent of CNS, 26.5 per cent of E. coli, 38.5 per cent of K. pneumoniae, 25 per cent of P. mirabilis and 55.6 per cent of P. aeruginosa strains.     

Susceptibility of Branhamella catarrhalis to antibiotics

A total of 98 isolates of Branhamella catarrhalis were examined for their susceptibility to antibiotics using serial dilution method. Nitrocefin test was employed for detection of beta-lactamase activity. It was found that most of the isolates (71%) were resistant to ampicillin. Resistance to this antibiotic was accompanied by ability to beta-lactamase production. On the other hand, all isolates were susceptible to amoxicillin + clavulanic acid combination. Almost all isolates were susceptible to cefaclor (99%), cefuroxime (94%), cefotaxime (100%), ciprofloxacin (100%), tetracycline (91%), cotrimoxazole (93%) and erythromycin (93%).     

Susceptibility to selected antibiotics of Yersinia enterocolitica 03 strains, carrying and not carrying plasmid pYV

A total of 199 clinical strains of Yersinia enterocolitica serotype O3, biotype 4 were tested for their susceptibility to antibiotics (158 strains carried the virulence plasmid pYV and 41 strains did not). 114 isolates were tested by standard disk diffusion method for 21 antibiotics. Almost all tested strains were resistant to ampicillin and cefazolin and susceptible to amoxycillin/clavulanate, cefaclor, cefamandole, cefuroxime, cefotaxime, ceftriaxone, aztreonam, imipenem, gentamicin, amikacin, netilmicin, tetracycline, doxycycline, chloramphenicol, ciprofloxacin, sulphamethoxazole, co-trimoxazole, trimethoprim and furazolidone. In addition minimal inhibitory concentrations (MICs) of 15 antibiotics were determined by agar dilution method for all 199 strains (158 plasmid positive and 41 strains plasmid negative). Third-generation cephalosporins such as cefotaxime and ceftriaxone and a fluoroquinolone (ciprofloxacin) were the most active antimicrobial agents, tested followed by aztreonam, imipenem, trimethoprim, tetracycline, gentamicin, chloramphenicol, amoxycillin/clavulanate, cefaclor, cefuroxime, amikacin, furazolidone and sulphamethoxazole. The present study demonstrated a high susceptibility of clinical strains of Y. enterocolitica to most of the tested antibiotics. In general, there was no significant difference between susceptibility of virulence plasmid pYV positive and virulence plasmid negative strains to antibacterial agents.     

Sensitivity of the wound microflora of oncological patients to some new antibiotics]

Sensitivity of the microflora of the oncological patients' wounds to the new antibiotics, such as gentamicin, kanamycin, oxacillin, ampicillin and lincomycin was studied with the help of the disc method. The discs with the above antibiotics were prepared under laboratory conditions in accordance with the respective instructions in the WHO. Sensitivity of 429 bacterial cultures, including 98 cultures of pathogenic staphylocci, 45 cultures of Enterococci, 43 hemolytic streptococci, 143 cultures of Escherichia, 50 cultures of Ps. aeruginosa and 50 cultures of Proteus was determined. The studies showed that gentamicin was the most active antibiotic aganist all the microbial species isolated from the surgical and other wounds of oncological patients. It may be used in treatment of the infections caused by association of the microbes belonging to different species, as well as in treatment of purulent processes before elucidating their etiology, 16.7 per cent of the Enterococcal isolates were resistant to gentamicin. Monomycin, kanamycin, oxacillin, lincomycin and macrolide antibiotics at present are sufficiently active against pathogenic staphylococci and hemolytic streptococci.     

Sulperazone in the treatment of severe infections in patients with cancer]

For the evaluation of rational sulperazone position in oncological hospital and elaboration of its implementation criteria investigation was performed. The trial included 193 patients (88 patients with injuries, 66 with hospital pneumonia, 39 with urinary track infection). From different clinical material of the patients were isolated 136 straines of Gram-negative bacteria. Suseptibile to sulperazone were 67 per cent of P. aeruginosa, 78-86 per cent of P. vulgaris, Klebsiella and E. coli isolates, 66 [symbol: see text] 60 per cent of Enterobacter and Serratia isolates subsequently. Comparative results of treatment with sulperazone as monotherapy and for combination with aminoglycosides (gentamycin or amicacin) in the case of P. aeruginosa infection demonstrated high sulperazone efficacy not lower than imipenem/cilsatatin and cefepime efficacy in the case of hospital infections treatment at critical care units. Low price of the sulperazone treatment when compared to imipenem/cilastatine is emphasized. Another advantage of sulperazone when compared to cefepime is anaerobic infection treatment--cefepime is administered in combination with metronidazole while sulperazone is used in monotherapy.