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Biomedical subjects

R Yogev

Publications and source records attributed to R Yogev.

At least 145 records · Page 8Linked to original sources
PubMed1982

Moxalactam in the treatment of pediatric infections.

The clinical efficacy and safety of the new oxacephalosporin moxalactam disodium were evaluated in 54 children with a variety of pediatric infections. Except for a terminally ill neutropenic leukemic patient with pneumonia and sepsis due to Pseudomonas aeruginosa who died shortly after initiation of therapy, moxalactam treatment was effective in all patients. No recurrent infections were observed. The rate of clinical response to moxalactam appeared to be at least comparable to that of patients treated with traditional antibiotics. In vitro sensitivity testing demonstrated that all bacteria isolated except P aeruginosa were sensitive to moxalactam while Haemophilus influenzae was exquisitely sensitive. Side effects included thrombocytosis (five patients), transient SGPT elevations and eosinophilia (three each), fever with rash (one), and neutropenia (one). In one patient, superinfection with Streptococcus faecalis developed. We conclude that moxalactam may be a useful antibiotic in pediatrics, particularly for the treatment of infections due to H. influenzae and Enterobacteriaceae. Its role in infections caused by group B streptococcus and Pseudomonas awaits further studies.

Adolescent↗
PubMed1982

In vitro development of rifampin resistance in clinical isolates of Haemophilus influenzae type b.

Although all of 14 clinical isolates of Haemophilus influenzae type b strains demonstrated rifampin susceptibility in vitro (minimal inhibitory concentration less than or equal to 0.4 microgram/ml) when an inoculum of 10(4) colony-forming units (CFU) was used, 10 of the 14 strains manifested resistance to this agent when an inoculum of 10(8) CFU was tested. The mutation rate for rifampin resistance ranged from 1 resistant colony per 3.5 x 10(6) CFU to 1 per 4 x 10(7) CFU. The emergence of rifampin-resistant mutants was prevented when trimethoprim was combined with rifampin. This finding suggests that when used alone for prophylaxis of H. influenzae type b nasopharyngeal carriers, rifampin is likely to lead to the emergence of resistant strains.

Colony-Forming Units Assay↗
PubMed1982

Elaboration of type b capsule by Haemophilus influenzae as a determinant of pathogenicity and impaired killing by trimethoprim-sulfamethoxazole.

In vitro, Haemophilus influenzae strains have two distinct patterns of susceptibility to trimethoprim-sulfamethoxazole (TMP/SMZ); strains with low minimum inhibitory concentration and high minimum bactericidal concentration (tolerant) and those with both low minimum inhibitory concentration and minimum bactericidal concentration (kill-sensitive). Tolerant H. influenzae strains were found to elaborate significantly more type b capsular polysaccharide, a linear polymer of ribosyl ribose phosphate (PRP), than kill-sensitive strains. Tolerant strains became susceptible to killing by TMP/SMZ when type b capsule was physically removed, but reacquired tolerance following growth and reversion to original (mucoid) phenotype. Susceptibility of wild (type a, b, c), isogenic (type b and untypable), and transformed (type b and d) strains indicated that elaboration of type b capsule was associated with TMP/SMZ tolerance. In a second series of studies, virulence of H. influenzae in the infant rat model was correlated with in vitro tolerance. Tolerant strains (13/13) caused systemic disease while none (0/7) of kill-sensitive strains were pathogenic. The efficacy of TMP/SMZ in the treatment of invasive infection was evaluated in rats with established bacteremia and meningitis. TMP/SMZ failed to eradicate H. influenzae b from the blood in 85% (17/20) or from the cerebrospinal fluid in 95% (19/20) of infected animals. Thus, in vitro tolerance correlated with therapeutic failure in vivo.

Animals↗
PubMed1982

Pulmonary paragonimiasis in Laotian refugee children.

Three Laotian refugee children with chronic pulmonary complaints and findings were found to have pulmonary paragonimiasis during a one-year period in Chicago. These patients ranged from 8 to 11 years of age and the diagnosis was delayed five to six months in two children because of the unfamiliarity of American physicians with signs and symptoms of this disorder. Clinical manifestations included chronic cough for up to two years, apparent hemoptysis in two patients, lack of fever or sweats, and family history negative for tuberculosis. Physical findings included rales and dullness to percussion, clubbing (one patient), and lack of fever or respiratory distress. All three patients showed interstitial infiltrates on chest roentgenogram whereas two had multiple small cystic areas. Moderate eosinophilia was present. Paragonimus westermani ova were found in stools of two patients, in sputum of two patients, and in bronchoscopic specimens in one patient. All patients demonstrated striking clinical and radiologic improvement following treatment with bithionol (50 mg/kg every other day for 15 doses), which was well tolerated. Lung fluke infestation must be considered in Indochinese refugee children with apparent hemoptysis or chronic pulmonary symptoms, and sputum and stool should be examined for P westermani ova.

Child↗
PubMed1981

Soft-tissue infections of ampicillin-resistant Haemophilus influenzae type b. The use of ampicillin and nafcillin in their treatment.

The combination of intravenous ampicillin sodium and nafcillin sodium followed by oral ampicillin and dicloxacillin sodium was effective in treating five infants with soft-tissue infections and bacteremia due to beta-lactamase-producing, ampicillin-resistant Haemophilus influenzae type b. This antibiotic combination seems to be an effective alternative to chloramphenicol for treatment of non-meningitic invasive disease due to moderately ampicillin-resistant (minimum inhibitory concentration, 2 to 24 microgram/mL) H influenzae type b. The use of this combination should be in conjunction with appropriate in vitro tests whose results demonstrate synergism.

Administration, Oral↗
PubMed1981

Penetrance of nafcillin into human ventricular fluid: correlation with ventricular pleocytosis and glucose levels.

Fourteen hydrocephalic pediatric patients with suspected shunt infections were studied for penetrance of nafcillin into the ventricular fluid after intravenous administration. In seven patients with bacterial ventriculitis, the concentration of nafcillin in ventricular fluid was 0.8 to 20.4% of the peak concentration in serum. In the remaining seven patients without bacterial ventriculitis, ventricular fluid levels ranged between less than or equal to 0.02 to 4% of peak serum concentrations. Although the degree of pleocytosis correlated poorly with penetrance, ventricular fluid glucose levels correlated inversely with penetrance of nafcillin (r = -0.7275, P less than 0.001).

Bacterial Infections↗
PubMed1981

In vitro and in vivo synergism between amoxicillin and clavulanic acid against ampicillin-resistant Haemophilus influenzae type b.

Eight strans of ampicillin-resistant beta-lactamase-producing Haemophilus influenzae type b were studied in vitro for synergy between amoxicillin and clavulanic acid. The minimal inhibitory concentrations for amoxicillin alone were 6.25 to 12.5 microgram/ml, and for clavulanic acid alone they were 12.5 to 25 microgram/ml. However, seven of eight strains were inhibited by a combination of 0.36 microgram of amoxicillin and 0.36 microgram of clavulanic acid per ml. Infant rat models of bacteremia and meningitis were used to test the efficacy of amoxicillin and clavulanic acid alone and in combination upon four strains of ampicillin-resistant H. influenzae. Neither amoxicillin alone (27 animals) nor clavulanic acid alone (20 animals) sterilized the blood or cerebrospinal fluid of the animals. In contrast, 30 of 33 blood cultures and 29 of 33 cerebrospinal fluid cultures were sterile when a combination of the two drugs in the same dosages was used. The observed in vitro and in vivo synergism between amoxicillin and clavulanic acid suggests that the combination may be effective therapy for invasive infections in humans caused by ampicillin-resistant H. influenzae type b.

Amoxicillin↗
PubMed1981

Intraventricular levels of amikacin after intravenous administration.

Serum and ventricular fluid pharmacokinetic data for amikacin were evaluated prospectively in 10 hydrocephalic children with suspected ventriculitis. After the fourth or fifth intravenous 7.5-mg/kg dose of amikacin given every 8 h, mean peak serum levels were 24.3 +/- 3.2 microgram/ml (achieved at 0.5 h) with a calculated half-life of 2.2 +/- 1.1 h. Mean peak ventricular fluid levels in five patients with bacterial infection were 6.1 +/- 2.0 microgram/ml (achieved at 3 h). In the remaining five patients without bacterial ventriculitis, very low levels (less than or equal to 0.7 microgram/ml) of amikacin were detected. Ventricular fluid pleocytosis was directly correlated and glucose levels were inversely correlated with penetration of amikacin. Systemic therapy with amikacin may be the treatment of choice for children with ventriculitis meningitis caused by bacteria which are highly susceptible to this drug, thereby permitting the avoidance of the potentially hazardous intraventricular route of administration.

Amikacin↗
PubMed1981

Nasopharyngeal carriage of Haemophilus influenzae type b: attempted eradication by cefaclor or rifampin.

The efficacy of cefaclor and rifampin in eradicating Haemophilus influenzae type b (HITB) from the nasopharynx of day care center and household contacts of children with HITB meningitis was evaluated. In 38/50 children treated with cefaclor, the carrier state persisted, a failure rate of 76%. Although cefaclor failed to eradicate HITB from many carriers, an appreciable reduction in the intensity of colonization following treatment was noticed. When rifampin was used in 17 children who had failed to respond to cefaclor, persistence of the carrier state with HITB was found in only two children, a failure rate of only 12%. During the study, two episodes of invasive HITB disease were documented to be acquired from sources other than the index cases or from children who were screened, which suggested the need to reevaluate the usually recommended strategy to screen for carriage and to treat only the immediate contacts 6 years of age and younger. Furthermore, the most appropriate agent for eradicating nasopharyngeal carriage of HITB awaits additional studies.

Adult↗
PubMed1981

Pharmacokinetic comparison of intravenous and oral chloramphenicol in patients with Haemophilus influenzae meningitis.

The pharmacokinetics of chloramphenicol following intravenous and oral administration were studied in 14 infants with Haemophilus influenzae meningitis. Following five days of treatment with intravenous chloramphenicol (100 mg/kg/day every six hours), oral chloramphenicol was substituted at the same dose. Multiple serum levels of chloramphenicol were determined after an intravenous dose on day 4 and after an oral dose on day 10. CSF levels were measured six hours after intravenous or oral chloramphenicol dose on those days (CSF trough). Following intravenous administration, the mean peak serum level of 15.0 micrograms/ml was reached at 45 minutes. In comparison, after oral chloramphenicol in the same dosage, the mean peak serum level of 18.5 micrograms/ml was achieved at two to three hours. The mean serum half-life of the drug (6.5 hours) was significantly longer after oral administration than after intravenous chloramphenicol (4.0 hours) (P less than .001). The increased serum half-life following orally administered chloramphenicol was occasionally associated with drug accumulation. In addition, mean trough CSF levels were somewhat higher when the patient received oral medication (6.6 micrograms/ml) compared to intravenous administration (4.2 micrograms/ml) (P less than .001). For any treatment regimen for H influenzae meningitis that includes a period of oral chloramphenicol therapy the patient should be hospitalized to ensure compliance. Because of the wide range of individual variation in serum half-life that may result in accumulation, periodic monitoring of serum chloramphenicol levels is also recommended.

Administration, Oral↗
PubMed1980

Synergistic action of ampicillin and nafcillin against ampicillin-resistant Haemophilus influenzae.

Six strains of ampicillin-resistant Haemophilus influenzae type b were studied in vitro for synergy between ampicillin and nafcillin. The minimal inhibitory concentrations for these strains with 10(4) colony-forming units per ml were 6.25 to 12.5 microgram of ampicillin per ml and 6.25 to 25 microgram of nafcillin per ml. Studies with these agents demonstrated synergism against all six strains of H. influenzae type b. Most strains were inhibited by 0.78 microgram of nafcillin plus 0.78 microgram of ampicillin per ml. A child with osteomyelitis caused by H. influenzae type b was successfully treated with a combination of ampicillin and nafcillin. These data suggest that further studies assessing the synergistic effect of this drug combination against H. influenzae type b are warranted.

Ampicillin↗
PubMed1980

Synergistic action of nafcillin and ampicillin against ampicillin-resistant Haemophilus influenzae type b bacteremia and meningitis in infant rats.

Infant rats with bacteremia and meningitis induced by ampicillin-resistant Haemophilus influenzae type b were treated with ampicillin and nafcillin, alone or in combination. Neither ampicillin alone (in 19 animals) nor nafcillin alone (in 20 animals) sterilized the blood or cerebrospinal fluid of any treated infant rat. When the combination of ampicillin and nafcillin was used, blood cultures were negative in 18 of 19 infant rats, and cerebrospinal fluid cultures were sterile in 15 of 19 when cultured 30 h after initiation of treatment. In vitro results demonstrated definite synergism between ampicillin and nafcillin against ampicillin-resistant H. influenzae type b. The study suggests that such synergism also exists in vivo.

Ampicillin↗