Antibiotic-resistant enterococci are often present in retail meats, but it is unclear whether the ingestion of these contaminants leads to sustained intestinal carriage.

A model of ascending unobstructed urinary tract infection (UTI) in mice was developed to study the significance of the antibiotic concentration in urine, serum, and kidney tissue for efficacy of treatment of UTI in general and pyelonephritis in particular. Outbred Ssc-CF1 female mice were used throughout the study, and Escherichia coli was used as the pathogen. The virulence of 11 uropathogenic E. coli isolates and 1 nonpathogenic laboratory E. coli strain was examined. Strain C175-94 achieved the highest counts in the kidneys, and this strain was subsequently used as the infecting organism. The model gave reproducible bladder infections, i.e., bacteria were recovered from 22 of 23 control mice after 3 days, and histological examination of kidney tissue showed that of 14 infected kidneys, 7 (50%) showed major histological changes, whereas 3 of 36 uninfected kidneys showed major histological changes ( P = 0.018). Once the model was established, the efficacies of different doses of cefuroxime and gentamicin, corresponding to active concentrations in urine only or in urine, serum, and kidney tissue simultaneously, were examined. All cefuroxime doses resulted in significantly lower counts in urine than control treatments, but the dose which produced concentrations of cefuroxime only in urine and not in serum or kidney tissue had no effect on kidney infection. Even low doses of gentamicin (0.05 mg/mouse) resulted in concentrations in renal tissue for prolonged times due to accumulation. All gentamicin doses had a significant effect (compared to the effect of the control treatment) on bacterial counts in urine and kidneys. The antibiotic effect on bacterial counts in bladders was negligible for unknown reasons. Use of the mouse UTI model is feasible for study of the effect of an antibiotic in the urinary system, although the missing antibacterial effect in the bladder needs further evaluation.

Antibiotics have played an essential role in decreasing morbidity and mortality from infectious diseases. However, indiscriminate use and unrestricted access is contributing to the emergence of bacterial resistance. This paper reports on a situational analysis of antimicrobial use and resistance in Ghana, with focus on policy and regulation. Relevant policy documents, reports, regulations and enactments were reviewed. PubMed and Google search engines were used to extract relevant published papers. Websites of stakeholders such as Ministry of Health (MOH) and its agencies were also reviewed. An interview guide was used to elicit responses from selected officials from these sectors. Laws and guidelines to control the use of antimicrobials in humans were available but not for animals. There was no National Antimicrobial Policy (NAP). A health practice regulatory law mandates Physicians, Physician Assistants, Midwives and trained Nurses to prescribe antimicrobials. However, antibiotics are widely prescribed and dispensed by unauthorised persons, suggesting weak enforcement of the laws. Antibiotics were also supplied to and from unapproved medicine outlets. The Standard Treatment Guidelines (STG), Essential Medicines List (EML) and the National Health Insurance Scheme Medicines List (NHISML) provide restrictions regarding levels of prescribing of antimicrobials. However, existing guidelines on antibiotic use are mostly not adhered to. The use of Automatic Stop Orders to avoid wastage in the hospitals is also not practiced. Data on use of antibiotics for individuals are not readily available in most facilities. Again, there are no standards or guidelines on veterinary use of antibiotics. Surveillance systems for consumption of antibiotics and resistance monitoring were not in place in most health facilities. However, there is an ongoing national action to create awareness on bacteria resistance, strengthening knowledge through research and surveillance and development of NAP in line with global action plan on antimicrobial resistance. Absence of national antimicrobial policy, weak regulatory environment and non-adherence to practice standards may have contributed to increased and unregulated access to antimicrobials in Ghana, a catalyst for development and spread of antimicrobial resistance.

The combination of β-lactam antibiotics and macrolides is often recommended for the initial empirical treatment of acute pneumonia in order to obtain activity against the most important pathogens. Theoretically, this combination may be inexpedient, as the bacteriostatic agent may antagonize the effect of the bactericidal agent. In this study, the possible interaction between penicillin and erythromycin was investigated in vitro and in vivo against four clinical isolates of Streptococcus pneumoniae with MICs of penicillin ranging from 0.016 to 0.5 mg/L and of erythromycin from 0.25 to >128 mg/L. In vitro time–kill curves were generated with clinically relevant concentrations of penicillin (10 mg/L) and erythromycin (1 mg/L), either individually or in combination. Antagonism between penicillin and erythromycin was observed for the four isolates. In vivo interaction was investigated in the mouse peritonitis model. After intraperitoneal inoculation, penicillin and erythromycin were given either individually or in combination. For two of the four isolates, mortality was significantly higher in the groups treated with the combination of penicillin and erythromycin than in the groups treated with penicillin alone [32/36 (86%) vs 3/12 (25%), P < 0.05; and 24/36 (67%) vs 3/12 (25%), P < 0.05, respectively]. Using the mouse peritonitis model, in vivo time–kill curves showed that there was antagonism between erythromycin and penicillin for the examined isolate. The antagonism demonstrated in vitro and in vivo between penicillin and erythromycin suggests that β-lactam antibiotics and macrolides should not be administered together unless pneumococcal infection is ruled out.