Readiness for antimicrobial resistance (AMR) surveillance in Pakistan; a model for laboratory strengthening.

BACKGROUND: Limited capacity of laboratories for antimicrobial susceptibility testing (AST) presents a critical diagnostic bottleneck in resource limited countries. This paper aims to identify such gaps and to explore whether laboratory networks could contribute towards improving AST in low resource settings. METHODS: A self-assessment tool to assess antimicrobial susceptibility testing capacity was administered as a pre-workshop activity to participants from 30 microbiology laboratories in 3 cities in Pakistan. Data from public and private laboratories was analyzed and capacity of each scored in percentage terms. Laboratories from Karachi were invited to join a support network. A cohort of five laboratories that consented were provided additional training and updates sessions over a period of 15 months. Impact of training activities in these laboratories was evaluated using a point scoring (0-11) tool. RESULTS: Results of self-assessment component identified a number of areas that required strengthening (scores of ≤60%). These included; readiness for AMR surveillance; 38 and 46%, quality assurance; 49 and 55%, and detection of specific organisms; 56 and 60% for public and private laboratories respectively. No significant difference was detected in AST capacity between public and private laboratories [ANOVA; p > 0.05]. Scoring tool used to assess impact of training within the longitudinal cohort showed an increase from a baseline of 1-5.5 (August 2015) to improved post training scores of 7-11 (October 2016) for the 5 laboratories included. Moreover, statistical analysis using paired t-Test Analysis, assuming unequal variance, indicated that the increase in scored noted represents a statistically significant improvement in the components evaluated [p < 0.05]. CONCLUSION: Strengthening of laboratory capacity for AMR surveillance is important. Our data shows that close mentoring and support can help enhance capacity for antimicrobial sensitivity testing in resource limited settings. Our study further presents a model wherein laboratory networks can be successfully established and used towards improving diagnostic capacity in such settings.

Clinical usefulness of components of the Triage immunoassay, enzyme immunoassay for toxins A and B, and cytotoxin B tissue culture assay for the diagnosis of Clostridium difficile diarrhea.

We studied 557 nonduplicate fresh stool specimens from adult patients clinically suspected of having Clostridium difficile-associated diarrhea. All samples were tested in parallel with an in-house cytotoxin B tissue culture assay (CTA), the C DIFFICILE TOX A/B II test (TA/B; TechLab, Blacksburg, VA), and the Triage Micro C DIFFICILE Panel (Biosite Diagnostics, San Diego, CA). The Triage device detects toxin A (TA) and glutamate dehydrogenase (GDH) simultaneously. Of the specimens, 350 were negative and 95 were positive for all markers. Another 112 specimens yielded discrepant results. The CTA found 143 positive specimens. Results of the components of the Triage and TA/B were compared separately with those of CTA. GDH was the most sensitive but least specific marker, whereas TA and TA/B were less sensitive but highly specific. Because of these attributes and a quick turnaround time, GDH would be the best screening test for C difficile-associated diarrhea. CTA detected the highest number of cases of C difficile-associated diarrhea and would be most useful as a confirmatory test for GDH-positive and TA-negative specimens.

Outbreak of Escherichia coli 0157:H7 related to animal contact at a petting zoo.

OBJECTIVE: To determine the cause of an outbreak of Escherichia coli 0157:H7 related to animal exposures so that further transmission could be prevented. DESIGN: Description of laboratory investigations and a case control study. SETTING: Agricultural pavilion at an annual fair in Ontario. POPULATION: People with laboratory evidence of E coli 0157:H7 (seven people) and others with diarrhea (155 people) who called the health unit following a media release were interviewed. Animals that were accessed most frequently by the public in the agriculture pavilion were tested for E coli 0157:H7. In the case control study, a case was defined as someone with laboratory confirmed E coli 0157:H7, or someone who developed severe or bloody diarrhea two to eight days after attending the agricultural pavilion at the fair (61 people). A convenience sample of people who attended the agricultural pavilion but did not develop diarrhea was selected as the control group (89 people). INTERVENTIONS: Human and animal E coli 0157:H7 specimens were subtyped. Cases and controls were interviewed using a standardized questionnaire. RESULTS: Subtyping of the seven human isolates of E coli 0157:H7 revealed five that were of an extremely uncommon phage type. Three samples from goats and one from sheep at the petting zoo in the agricultural pavilion were of this same phage type. The case control study also implicated goats (odds ratio [OR] 3.65; 95% CI 1.63 to 8.52) and sheep (OR 2.94; 95% CI 1.33 to 6.57) from the petting zoo. CONCLUSIONS: Results of this investigation suggest strongly that the goats and sheep from the petting zoo were the source of this outbreak of E coli 0157:H7.