Microbiological analysis and predictors of gallbladder infection with antimicrobial susceptibility patterns in an HIV setting

Background South Africa has a high prevalence of people living with human immunodeficiency virus (HIV; PLWH) who have shown to affect the prevalence and severity of infection and sepsis particularly gallbladder disease.  Empirical Antimicrobial (EA) therapy for acute cholecystitis (AC) is based largely on bacteria colonisation of bile (bacteriobilia) and antimicrobial susceptibility patterns (antibiograms) obtained from the developed world where the prevalence of PLWH is very low. In an ever-emerging era of increasing antimicrobial resistance, monitoring and updating local antibiograms is underscored.  Objective Due to the paucity of data available locally to guide treatment we found it pertinent to examine gallbladder bile for bacteriobilia and antibiograms in a setting with a high prevalence of PLWH to determine if this may demand a review of our local antimicrobial policies for gallbladder infections for both EA and pre-operative antimicrobial prophylaxis (PAP) for laparoscopic cholecystectomies (LC). Methodology A retrospective observational descriptive study was undertaken at King Edward VIII Hospital, Durban, KwaZulu-Natal, South Africa. Hospital records were reviewed for all patients undergoing cholecystectomy over a 3-year period. Gallbladder bacteriobilia and antibiograms were assessed and compared between PLWH and HIV uninfected (HIV-U). Pre-operative age, ERCP, PCT, CRP and NLR were used as predictors for bacteriobilia. Statistical analyses were performed using R Project and p values of less than 0.05 were considered as statistically significant. Results There were no differences in bacteriobilia or antibiograms between PLWH and HIV-U. There was >30% resistance to amoxicillin/clavulanate and cephalosporins. Aminoglycoside-based therapy, had good susceptibility patterns whilst carbapenem-based therapy demonstrated the lowest resistance levels. ERCP and age were predictors of bacteriobilia (p<0.001 and 0.002 respectively). PCT, CRP and NLR were not. Conclusion PLWH should follow the same PAP and EA recommendations as HIV-U. For EA, we recommend, a combination of amoxicillin/clavulanate with aminoglycoside-based therapy (amikacin or gentamycin) or piperacillin/tazobactam as monotherapy. Carbapenem-based therapy should be reserved for drug resistant species. For PAP, we recommend the routine use in older patients and patients with history of ERCP undergoing LC.

Carbapenem-resistant Enterobacteriaceae in patients with bacteraemia at tertiary hospitals in South Africa, 2015 to 2018

Enhanced surveillance for CREs was established at national sentinel sites in South Africa. We aimed to apply an epidemiological and microbiological approach to characterise CREs and to assess trends in antimicrobial resistance from patients admitted to tertiary academic hospitals. A retrospective analysis was conducted on patients of all ages with CRE bacteraemia admitted at any one of 12 tertiary academic hospitals in four provinces (Gauteng, KwaZulu-Natal, Western Cape and Free State) in South Africa. The study period was from July 2015 to December 2018. A case of CRE bacteraemia was defined as a patient admitted to one of the selected tertiary hospitals where any of the Enterobacteriaceae was isolated from a blood culture, and was resistant to the carbapenems (ertapenem, meropenem, imipenem and/or doripenem) or had a positive result for the Modified Hodge Test (MHT) according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. A positive blood culture result obtained after 21 days of the last blood culture result was regarded as a new case. To distinguish hospital-acquired (HA) from the community-acquired (CA) bacteraemia, the following definitions were applied: the HA CRE bacteraemia was defined as a patient with CRE isolated from blood culture ≥ 72 h of hospital admission or with any prior healthcare contact, within 1 year prior to the current episode or referral from a healthcare facility where the patient was admitted before the current hospital. A case of the CA CRE bacteraemia was defined as a patient with CRE isolated from blood culture < 72 h of hospital admission and with no prior healthcare contact. The majority of carbapenem-resistant Enterobacteriaceae (CRE) (70%) were hospital-acquired (HA) with Klebsiella pneumoniae being the predominant species (78%). In-hospital mortality rate was 38%. The commonest carbapenemase genes were bla-_OXA-48 (52%) and bla-_NDM (34%). The high mortality rate related to bacteraemia with CRE and the fact that most were hospital-acquired infections highlights the need to control the spread of these drug-resistant bacteria. Replacement with OXA-48 is the striking finding from this surveillance analysis. Infection control and antibiotic stewardship play important roles in decreasing the spread of resistance.