Effects of imipenem and meropenem on serum sensitivity and surface hydrophobicity of Klebsiella pneumoniae

We report a case of hyperimmunoglobulin E syndrome (HIE) complicated by neutrophil deficiency which was successfully treated with oral administration of disodium cromoglycate. A 48-year-old Japanese man with HIE developed Streptococcus pneumoniae meningitis. Laboratory tests after the meningitis revealed persistent neutropenia (300-800/mm3) and defects of phagocytosis and bacterial killing by neutrophils. Administration of disodium cromoglycate was started, and neutrophil counts gradually increased to 1200-1600/mm3. The impaired neutrophil activities returned to normal. The patient improved clinically; during the 2-year treatment, he had only two brief episodes of the common cold. Disodium cromoglycate may have potential clinical use in the treatment of cases of HIE even with neutrophil deficiency.     

In vitro activity of netilmicin compared with gentamicin, tobramycin, amikacin, and kanamycin

The in vitro activity of netilmicin was compared with that of gentamicin, tobramycin, amikacin, and kanamycin against 636 strains of bacteria recently isolated from clinical sources. Gentamicin was the most active antibiotic, but netilmicin and tobramycin closely paralleled it. Netilmicin was generally four-to eightfold less active than gentamicin against Serratia and group A streptococci, and was twofold less active against Pseudomonas aeruginosa. When effects of inoculum size and concentration of divalent cations in the media were evaluated, netilmicin was shown to be similar to gentamicin in vitro. Minimum inhibitory concentrations for P. aeruginosa were increased as much as 18-fold when the Mg(2+) and Ca(2+) concentrations were increased to physiological levels in Mueller-Hinton broth.     

Resistance to gentamicin, tobramycin and amikacin among clinical isolates of bacteria

Susceptibility to the administration of gentamicin, tobramycin and amikacin was determined for all isolates of aerobic and facultative gram-negative bacilli submitted for testing to the clinical bacteriology laboratory of the Massachusetts General Hospital between July 1, 1974, and June 30, 1976. In this 24-month period more than 46,000 isolates of bacteria were tested by the single-disc diffusion (Bauer-Kirby) method. Resistance to one or more of the aforementioned aminoglycosidic aminocyclitol antibiotics was found among 4,114 stains. Correlation with quantitative susceptibility test methods revealed that disc-diffusion methods using 10 microng discs accurately predicted resistance to gentamicin and tobramycin, but overestimated the prevalence of resistance to amikacin by 20 to 60%. Most of the gentamicin-resistant Enterobacteriaceae in this study were also cross-resistant to tobramycin but were susceptible to amikacin. Many gentamicin-resistant strains of Ps. aeruginosa were susceptible to both tobramycin and amikacin. Resistance to amikacin tended to be of relatively low magnitude (most had minimal inhibitory concentrations (MIC's) between 31 and 125 microng/ml), but organisms which were resistant to the administration of amikacin were usually resistant to the other two aminoglycosidic antibiotics as well.     

Klebsiella pneumoniae clinical isolates: susceptibility to some antibiotics and surface hydrophobicity

The susceptibility of Klebsiella pneumoniae strains isolated from the respiratory tract (55), urinary tract (19) and other human body sites (8) to the antibiotics, amoxycillin/clavulanate, cefuroxime, ceftazidime, gentamicin, norfloxacin, colistine, cotrimoxazole and oxolinic acid, as well as their surface hydrophobicity, were studied. The strains expressed a very high sensitivity to the antibiotics (94.7-100%). The surface hydrophobicity of the strains was evaluated by means of three assays and was minimal. The hydrophobicity manifested by adherence to xylene ranged between 0 and 10% for 96.4% of the respiratory strains, and for 100% of the urinary and other sites. Weak binding of Congo red (10-29 micrograms/10(10) cells) showed 96.4% of respiratory isolates as well as 100% of the urinary and other strains. Results of the salt aggregation test showed that 96.4% of respiratory strains and 100% of urinary and other strains aggregated only at 1.5 M, 2 M or higher concentrations.     

Pharmacokinetic properties of gentamicin and amikacin in the cockatiel

Gentamicin and amikacin are commonly used in veterinary medicine to treat a variety of gram-negative bacterial infections. The present study evaluates the pharmacokinetics of gentamicin sulfate and amikacin sulfate in the cockatiel (Nymphicus hollandicus), a small (approximate body weight = 100 g) psittacine bird, utilizing treatment regimens developed in larger parrot species. Serum antibiotic concentrations were determined in cockatiels following twice-daily intramuscular treatment with 5 mg gentamicin/kg body weight and 15 mg amikacin/kg body weight. In the present study, peak values of gentamicin were 4.6 +/- 1.45 micrograms/ml, and trough values were 0.17 +/- 0.04 micrograms/ml. Amikacin administration resulted in peak values of 27.3 +/- 6.9 micrograms/ml and trough concentrations of 0.9 +/- 0.3 micrograms/ml. Based on the present study, an appropriate intramuscular dose regimen for gentamicin in cockatiels is 5 to 10 mg/kg body weight either two or three times per day. An intramuscular amikacin dosage of 15 to 20 mg/kg body weight either two or three times per day is recommended for treatment of infections caused by susceptible bacteria.     

Analysis of neomycin, kanamycin, tobramycin and amikacin resistance mechanisms in gentamicin-resistant isolates of Enterobacteriaceae

Twenty-four gentamicin-resistant isolates of Enterobacteriaceae, obtained from the clinical laboratories of three health centres in Nablus, Palestine, were tested for susceptibility to neomycin, kanamycin, tobramycin and amikacin. Resistance rates were 29.2% for neomycin, 58.3% for kanamycin, 45.8% for tobramycin and 8.3% for amikacin. Fourteen (58.3%) isolates were noted to be multiresistant, i.e., resistant to gentamicin and two or more other aminoglycosides; resistance to gentamicin, kanamycin and tobramycin was the most common pattern of multiple resistance. This pattern implies the involvement of adenyltransferase ANT(")-I activity. Plasmid profiles and curing experiments suggested a plasmid localisation of gentamicin, neomycin, kanamycin and tobramycin resistance genes. However, a chromosomal location is proposed for plasmid-deficient strains. Cross-resistance in two isolates to all aminoglycosides tested suggested membrane impermeability to aminoglycosides as the mechanism of resistance.     

Resistance to amikacin and isepamicin in rabbits with experimental endocarditis of an aac(6')-Ib-bearing strain of Klebsiella pneumoniae susceptible in vitro

The effect of production of the aminoglycoside 6'-N-acetyltransferase [AAC(6')-IB] in Klebsiella pneumoniae on the outcome of amikacin and isepamicin treatment of rabbits with experimental endocarditis was assessed. Isogenic high-level (Hi) and low-level (Lo) AAC(6')-Ib-producing transconjugants (T) were constructed from clinical isolates with plasmid-borne resistance determinants. The MICs of amikacin and isepamicin, their bactericidal effects, and AAC(6')-Ib production appeared to be well correlated among the clinical isolates and the transconjugants. The susceptibility data determined in vitro, with MICs (in micrograms per milliliter) of amikacin and isepamicin for LoT and HiT of 4 and 0.5 and 32 and 8, respectively, were, however, not predictive of the in vivo efficacies of the drugs. While amikacin and isepamicin caused reductions in bacterial densities (log10 CFU per gram of cardiac vegetation) of 5.1 and 4.8 of the fully susceptible recipient strain (MICs of amikacin and isepamicin, 0.5 and 0.25, respectively), the reductions in density of both LoT and HiT caused by the two drugs (2.7 and 2.4 and 2.9 and 2.2, respectively) were only marginally significant, if at all. There was no significant difference (P > 0.05) when the reductions in density of LoT and HiT by either drug were compared or when the efficacies of the two drugs in reducing the density of any strain [non-AAC(6')-producing, LoT, or HiT] were compared (P > 0.5). It is concluded that AAC(6')-Ib in K.pneumoniae, even when produced at a low level and not conferring resistance to amikacin and isepamicin in vitro, compromises the efficacies of both drugs in vivo and possibly does so beyond the experimental model studied here.     

Comparison of the bactericidal action of amikacin, netilmicin and tobramycin in free and liposomal formulation against Pseudomonas aeruginosa

Glycoprotein Ibalpha (GP Ibalpha; CD 42b; hereafter GPIBA) is a component of the cell surface receptor for the von Willebrand factor (vWf) on platelets. Immunizations against various platelet surface antigens play a major role in neonatal alloimmune thrombocytopenia and in post-transfusion purpura. Only one antigenic polymorphism in GPIBA has thus far been established: the HPA-2 (Ko) alloantigen system. To screen other polymorphisms in GPIBA systematically, we analyzed the whole coding sequence of the GPIBA gene in 50 Finnish blood donors using the single-strand conformation polymorphism method. In addition to the known polymorphisms, we detected three others. Sequencing of the gene segments carrying the new polymorphisms revealed that none of them changed the predicted amino acid sequence. Polymorphism designated RS was located five base pairs upstream from the initiation codon at position 3064 and had the gene frequency of 16% for R and 84% for S, respectively, in the Finnish population, and it was detectable by the restriction enzyme Hae III. The EF polymorphism was at position 3842 (Asn242) and the gene frequencies were 97% for E and 3% for F. The KL polymorphism was at position 4142 (Arg342) and the gene frequencies were 98% for K and 2% for L. The five polymorphic positions in GPIBA formed altogether six different alleles of the gene. The data suggest that there are only a few variable amino acids in GPIBA.     

Extended-spectrum beta-lactamases in clinical isolates of Klebsiella pneumoniae from Zagreb, Croatia

Forty clinical isolates of Klebsiella pneumoniae, from various clinical specimens, with reduced susceptibility to ceftazidime, were tested for extended-spectrum beta-lactamase (ESBL) production. ESBL production was demonstrated by an 8-fold reduction in the minimum inhibitory concentration (MIC) of ceftazidime combined with clavulanate (2 mg/L) compared to ceftazidime alone in all strains. The aim of this investigation was the biochemical and molecular characterization of the ESBL produced by K. pneumoniae strains and their Escherichia coli transconjugants. Transfer of ceftazidime resistance was demonstrated in 23 of 40 strains. Thirteen strains produced an ESBL with the isoelectric point of 8.2 which was encoded by a self-transferable multiresistance plasmid of 150 kb. The substrate profile was similar to that of the SHV-5 isolated initially in Chile. Seven of these 12 strains had an additional TEM beta-lactamase. Six isolates and their transconjugants produced a plasmid-encoded ESBL with an isoelectric point close to 5.4. The remaining 21 strains produced an ESBL with an isoelectric point of 7.6 (thus probably SHV-2) which was encoded on a plasmid transferable to E. coli in 4 strains only. Four of those strains possessed an additional plasmid encoded TEM beta-lactamase with an isoelectric point close to 5.4. The transconjugants harbored a multiresistance plasmid of 150 kb. Thus SHV-2 and SHV-5 enzymes appear to have been the most common ESBLs in K. pneumoniae from Zagreb during 1994-1995.     

Involvement of T cells in enhanced resistance to Klebsiella pneumoniae septicemia in mice treated with liposome-encapsulated muramyl tripeptide phosphatidylethanolamine or gamma interferon

We have previously shown that prophylactic administration of the liposome-encapsulated immunomodulating agents muramyl tripeptide phosphatidylethanolamine (MTPPE) and gamma interferon (IFN-gamma) results in strongly increased survival of mice from a normally lethal septicemia with Klebsiella pneumoniae. It was anticipated that the treatment acts on macrophages and nonspecifically augments host resistance to various infections. In the present study, we provide evidence for a key role for T cells in host defense potentiation by the liposomal immunomodulators toward K. pneumoniae septicemia. It is shown that both CD4 and CD8 cells are important in immunomodulation, most likely due to production of IFN-gamma. Depletion of circulating IFN-gamma resulted in strong reduction of the antimicrobial host defense activation. Administration of interleukin-10 resulted in decreased antimicrobial host defense activation by liposomal immunomodulators. Moreover, administration of liposomal immunomodulators was shown to induce predominantly T-helper type 1 (Th1) cell populations in the spleen. These findings indicate that immunomodulation with liposomal MTPPE and IFN-gamma favors Th1 and NK cell activation.     

Serum concentrations and inhibitory ratios during amikacin therapy of gram-negative infections

The ratio of the peak serum concentration after a 500-mg dose of amikacin to the pathogen minimum inhibitory concentration was determined for 95 patients under treatment for serious Gram-negative infections. There were 113 such ratios. The relationship of this inhibitory ratio to the clinical effectiveness and side effects of treatment with this new aminoglycoside was also studied. Mean peak serum concentration of drug was 25.8 microgram/ml, and mean inhibitory ratio was 13.0. Ninety-six per cent of inhibitory ratios were greater than or equal to 1.0. Therapy was rated totally effective in 85% of patients clinically evaluated and partially effective in 3%. Signs of renal or eighth cranial nerve impairment attributable to drug administration were confined to only two patients, and there were no other side effects. The reliability of amikacin therapy appears to be related to dependable serum levels and high inhibitory ratios.     

Molecular cloning, sequencing and characterization of the genes for adenosylcobalamin-dependent diol dehydratase of Klebsiella pneumoniae

Klebsiella pneumoniae and some of the other Enterobacteriaceae form both diol dehydratase and glycerol dehydratase in response to growth substrates. To compare these enzymes produced by the same bacterium, the pdd genes of K. pneumoniae encoding adenosylcobalamin-dependent diol dehydratase were cloned and sequenced. The sequential three open reading frames (pddA, pddB, and pddC genes) encoded polypeptides of 554, 228, and 174 amino acid residues with predicted molecular weights of 60,379(alpha), 24,401(beta), and 19,489(gamma), respectively. The deduced amino acid sequences of the subunits were 84-100% and 54-71% identical with those reported for diol dehydratases and glycerol dehydratases, respectively.     

Acute bronchiolitis due to Mycoplasma pneumoniae and successfully treated with steroids

A high fever, coughing, stridor, and dyspnea developed in a 52-year-old woman on October 19, 1995. She went to a local clinic and was treated with oral penicillin and intravenous cefpirome. The symptoms worsened, and she was admitted to our hospital on October 26. Coarse crackles and wheezing were heard in both lung fields. The white blood cell count was 9000/mm3 and arterial blood gas analysis revealed a PaO2 of 49.8 Torr on room air. A chest roentgenogram obtained on admission showed a few small bibasilar nodular infiltrates, and a chest CT scan showed thickened bronchial walls along with small nodules having a centrilobular distribution. Of the cells in bronchoalveolar lavage fluid, 88% were neutrophils, but tests for bacteria and mycobacteria were negative. The cold-agglutinin titer was 1:512. The Mycoplasma pneumoniae antibody titer (IIIA) was 1:640 and viral serology tests were negative. Acute bronchiolitis due to M. pneumoniae was diagnosed and treatment with intravenous minocycline was started. The symptoms (coughing, fever, and stridor) resolved and the small nodules on chest CT scan disappeared, but hypoxemia remained. At the same time, an obstructive ventilatory defect (FEV1% 62.8%) and abnormal ventilation/perfusion lung scans were noted. Development into bronchiolitis obliterans was suspected, so administration of methyl prednisolone (1 g/day for 3 days) and prednisolone was started. The response to steroids was good. Pulmonary function improved and the arterial PaO2 at the time of discharge was 86 Torr (room air). Use of steroid therapy in the early phase of bronchiolitis obliterans seemed to be effective.     

Serum calcium, phosphate and alkaline phosphate levels in epileptic children treated with phenobarbitone

A longitudinal study to estimate the serum calcium, phosphate and alkaline phosphatase levels of 89 ambulatory epileptic children, aged between 3 years and 12 years, and having generalised tonic-clonic seizures, was carried out. None was on any form of medication for the treatment of seizures prior to presentation. Each patient received only phenobarbitone during the period of study. Serum levels of the biochemical parameters were determined at presentation, 6 months and 12 months, while serum phenobarbitone levels were estimated at 6 months and 12 months. Mean serum calcium, phosphate and alkaline phosphatase of the patients remained within the normal range. Using the paired 't' test, the differences in the levels of the parameters at the three measurements were not statistically significant (P > 0.05). Serum phenobarbitone levels remained within the therapeutic range during the period of study. Our results show that over a 12-month period, serum levels of calcium, phosphate, and alkaline phosphatase, remain normal in ambulant epileptic children treated with phenobarbitone.     

Effects of carbohydrate chain on surface net charge and hydrophobicity of glycoenzymes

OBJECTIVE: To study the origin of the different components of the electroretinogram (ERG) elicited by a random binary m-sequence stimulus. METHODS: Electroretinograms were recorded from pigmented rabbits before and after the injection of glutamate analogues (2-amino-4-phosphono-butyric acid [APB; DL form] and cis-2,3-piperidine-dicarboxylic acid [PDA]) and inhibitory neurotransmitters (glycine and gamma-aminobutyric acid [GABA]) to abolish the contribution of different cell types to the ERG. Two types of stimuli were used: conventional full-field stimulation with short- and long-duration flashes and a random binary m-sequence of flashes designed to mimic the pseudorandom binary m-sequence stimulation used in the multifocal ERG technique. RESULTS: The effects of APB and PDA on the first-order kernel of the random ERGs were similar to those on the photopic short-flash ERG. Glycine and GABA minimized the oscillatory potentials (OPs) of the photopic ERGs, and also reduced the amplitude of the positive wave of the first-order kernel slightly but caused a large reduction in the amplitude of the second-order kernel. CONCLUSIONS: The data suggest that the ON and OFF bipolar cells contribute significantly to the photopic short-flash ERG, as previously shown, and to the first-order kernel of the responses elicited by the pseudorandom binary sequence stimuli. The second-order kernel and the OPs receive a strong contribution from the cells of the inner retinal layers.     

Methodological aspects of Klebsiella pneumoniae serotyping and its use for characterization of clinical isolates

The method for serological typing of Klebsiella pneumoniae making use of Russian commercial K-sera manufactured by the Ilya Metchnikoff firm has been used to characterize 85 strains isolated from newborns at an obstetrical hospital and department of newborn diseases and from children with acute enteric infections hospitalized at the hospital for infectious diseases. The authors emphasize that their methods of serotyping are to be accurately performed, specifically, the selection of capsular forms and identification of serovars in strains which can be agglutinated by several sera. Serovars were identified by the proposed serotyping method in 89.4% of the studied strains. A wide spectrum of K-serovars typical of this or that hospital has been defined for each institution. K. pneumoniae K2 predominated in the obstetrical hospital, K. pneumoniae K24 and K25 prevailed in department for newborn diseases, and the K14 variant in the infectious diseases hospital.