Osteomyelitis in infants and children. A review of 163 cases.

One hundred sixty-three cases of osteomyelitis in infants and children were seen at our hospital during the past 15 years. There were twice as many boys as girls. Staphylococcus aureus was the major etiologic agent, being identified in 61% of the cases. Gram-negative bacteria were responsible for only 14 cases (9%). The femur, the tibia, or the humerus were affected in 103 of the 152 patients with single bone involvement. Ostoemyelitis of more than one bone was seen in 11 cases (7%). Associated joint infectin was confirmed in 29 patients. There were no deaths. Surgical drainage was carried out in 81 cases (50%). Ten patients had recurrent or persistent drainage and one developed a Brodie abscess. Of the patients with S aureus osteomyelitis, chronic disease occurred in 19% of those receiving parenterally administered antibiotics for three weeks or less, but in only one patient (2%) of those who received parenteral antibiotics longer than three weeks.

Colicin types of Shigella sonnei in relation to antibiotic resistance.

Colicin typing of 436 strains of Shigella sonnei isolated in Dallas during a 10-year period was performed to determine whether resistance to ampicillin was associated with a single strain or was widespread among all S. sonnei types. One hundred ninety-three strains collected during a period of eight and one-half years when ampicillin resistance was 1.6% were available for retrospective review. During the last one and one-half years of study, 20.6% of the 243 strains that represented almost all S. sonnei isolated in Dallas were resistant to ampicillin. More than 50% of the strains collected annually were colicin type 9,22% were untypable, and seven other types were less frequently encountered. Resistance to ampicillin increased slightly from 1.5% to 9.5% among the type 9 strains, and one type 8 strain (2.9%) was resistaiple resistance to seven antibiotics tested was found mainly in untypable strains. Thus it appears that the abrupt increase in ampicillin resistance in mid-1972 was due principally to resistance in a single biotype, and that resistance is not widespread among all types of S. sonnei.

Comparative efficacy of cephalexin and ampicillin for shigellosis and other types of acute diarrhea in infants and children.

Most ampicillin-resistant Shigella are susceptible to cephalexin. Randomized treatment with cephalexin or ampicillin was given to 154 infants and children with acute diarrhea. Rectal swab cultures revealed Shigella in 42%, Salmonella in 6%, enteropathogenic Escherichia coli in 2%, and no pathogen in 50%. Cephalexin failed to eradicate Shigella after 5 days of treatment in 76% of patients as contrasted with 28% of ampicillin-treated patients with susceptible organisms. Shigella persisted in 78% of ampicillin-treated patients with resistant organisms. Diarrhea lasted more than 5 days in 43% of cephalexin-treated patients, in 56% of the ampicillin group with resistant organisms, but in only 9% of ampicillin-treated patients with susceptible organisms. The failure of cephalexin was due to the relatively high minimal inhibitory concentrations and minimal bacterial concentrations of 5 or 10 mug/ml and, although serum concentrations were twice the minimal bacterial concentration, they were not sufficient to demonstrate killing by the serum dilution method. In vitro susceptibility or resistance of Shigella to ampicillin correlated with clinical success or failure. Cephalexin is not a suitable drug for treatment of shigellosis in patients with ampicillin-resistant organisms.

Ampicillin in Haemophilus influenzae meningitis. Clinicopharmacologic evaluation of intramuscular vs intravenous administration.

Sixty-two children with Haemophilus meningitis were treated with ampicillin sodium, 200 mg/kg/day for ten days. Thirty-one received the drug intravenously (IV) for ten days; the other 31 patients received ampicillin IV for five days (except for one test dose given intramuscularly [IM] on day 2) followed by IM administration of ampicillin the last five days. Ampicillin concentrations in cerebrospinal fluid (SCF) were higher one hour after IV administration, but at two and four hours, concentrations were greater after IM doses. Responses to therapy and rates of complications were similar in the two groups. Fourteen patients had positive CSF cultures on day 2. Ten of these were isolated only on Levinthal medium and would have been overlooked with routine culture methods. All organisms were ampicillin-susceptible and all CSF cultures were negative by 48 hours. More patients with delayed sterilization had neurologic sequelae (78%) than patients with prompt CSF sterilization (13%). The schedule of five days of IV treatment followed by five days of IM therapy was pharmacologically and clinically as effective as ten days of IV therapy and has practical advantages.

In vitro susceptibility of Shigella strains to trimethoprim and sulfamethoxazole.

Trimethoprim and sulfamethoxazole were tested alone and in combination against 227 recently isolated Shigella strains. Variations in medium constituents and inoculum size were used to determine the optimal testing conditions. The plate dilution method with addition of 5% lysed horse blood to the susceptibility test medium and an inoculum size of 10(2) organisms was found to provide satisfactory results. All 227 strains were inhibited by low concentrations of trimethoprim, and all were susceptible to the combination of 0.06 mug of trimethoprim per ml and 1.25 mug of sulfamethoxazole per ml. Sixteen percent of these strains were resistant to ampicillin, 33% to tetracycline, 15% to chloramphenicol, and 27% to cephalothin. Based on these in vitro observations, trimethoprim and sulfamethoxazole appear worth evaluating for treatment of shigellosis due to multiply antibiotic-resistant strains.