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.

Antimicrobial susceptibility patterns of uropathogens isolated from pregnant women in KwaZulu-Natal Province: 2011 - 2016.

BACKGROUND: Urinary tract infection (UTI) is one of the most common infections during pregnancy, which can lead to significant maternal and perinatal morbidity and mortality if left untreated. Challenges when treating UTIs in pregnancy include fetal protection and resistance development of uropathogens. Currently, the Essential Medicines List recommends nitrofurantoin to treat cystitis and ceftriaxone to treat pyelonephritis in pregnant women. OBJECTIVES: To determine common pathogens causing UTI in pregnancy and their antibiotic susceptibility patterns. METHODS: A retrospective analysis was performed of laboratory data for positive urine specimens from obstetric departments of 6 KwaZulu- Natal Province hospitals during 2011 - 2016. Identification and susceptibility testing were performed using the VITEK 2 system. Results were interpreted according to the breakpoints of the Clinical and Laboratory Standards Institute, USA. RESULTS: From 5 971 positive urine specimens, the most common isolate was Escherichia coli (n=3 236; 54.2%), followed by Klebsiella pneumoniae (n=770; 12.9%). Group B streptococcus (GBS) (n=239; 4.0%) and Enterococcus faecalis (n=251; 4.2%) were the most common Gram-positive pathogens. E. coli displayed significant resistance to trimethoprim-sulfamethoxazole (65.1%), cephalothin (38.3%), cefuroxime (27.3%), ciprofloxacin (16.9%) and amoxicillin-clavulanic acid (17.1%). Resistance to ceftriaxone and nitrofurantoin remained low ‒ 9.1% and 7.7%, respectively. Among Gram-positive pathogens, GBS displayed 100% penicillin susceptibility and E. faecalis showed 92.9% susceptibility to ampicillin. CONCLUSIONS: E. coli is unsurprisingly the most common cause of UTI in pregnancy in KwaZulu-Natal. Susceptibility to ceftriaxone and nitrofurantoin remains good. Among Gram positives, GBS is prevalent and susceptible to penicillin, while E. faecalis is susceptible to ampicillin. As antimicrobial resistance evolves, routine surveillance is necessary to modify recommended empirical antibiotic use.

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.

Amikacin-resistant Acinetobacter species mediated by the aphA6 gene associated with clinical outcome at an academic complex hospital in KwaZulu-Natal Province, South Africa.

BACKGROUND: Drug-resistant Acinetobacter species present serious therapeutic and infection control policy challenges globally. Although aminoglycosides have played a crucial role in the treatment of infections with multidrug-resistant (MDR) Acinetobacter spp., recent reports indicate that these bacteria are developing resistance to aminoglycosides around the globe. OBJECTIVES: To determine the association between amikacin resistance and clinical outcomes of patients. The minimum inhibitory concentrations (MICs) of amikacin against Acinetobacter spp. and genes associated with resistance were also investigated. METHODS: Clinical information from 107 patients with Acinetobacter spp. cultured from clinical specimens was recorded during ward rounds at an academic complex hospital in KwaZulu-Natal Province, South Africa, including clinical outcomes, history of antibiotics prescribed and microbiological investigations. The 107 Acinetobacter isolates were investigated for susceptibility to antimicrobial agents in use at local hospitals. Genes related to amikacin resistance (aphA6 and aacA4) were investigated by polymerase chain reaction (PCR) and sequencing. Analysis was performed on the relationship between clinical outcomes and antimicrobial resistance patterns, as well as on the amikacin MICs in resistant isolates (n=6) v. their PCR results. RESULTS: The majority (5/6, 83.3%) of patients with amikacin-resistant Acinetobacter infection were discharged, and 1/6 (16.7%) died. No underlying clinical factors were significantly associated with clinical outcome. Amikacin resistance was observed in 6/107 isolates (5.6%), with MICs of 32 µg/mL (n=3) and ≥64 µg/mL (n=3) for the amikacin-resistant isolates. All 6 of these isolates were also extensively drug-resistant (XDR). The aphA6 gene (797 base pair) was detected in all amikacin-resistant isolates. CONCLUSIONS: Most tested Acinetobacter isolates were susceptible to amikacin, underscoring the crucial role of this antibiotic in the treatment of MDR Acinetobacter spp. in our hospital. The emergence of XDR isolates is of serious concern and necessitates close monitoring and surveillance.

Surveillance and comparison of antimicrobial susceptibility patterns of ESKAPE organisms isolated from patients with bacteraemia in South Africa, 2016 - 2017.

BACKGROUND: In South Africa (SA), the National Department of Health has developed an Antimicrobial Resistance National Strategy Framework document to manage antimicrobial resistance (AMR). One of the strategic objectives is to optimise surveillance and early detection of AMR. At the National Institute for Communicable Diseases (NICD), an analysis of selected organisms and antimicrobial agents from both the public and the private sectors was conducted. OBJECTIVES: The relevance of surveillance for AMR is increasingly recognised in the light of global action plans to combat resistance. In this report, we present an overview of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) organisms and Escherichia coli reported from public and private sector laboratories in SA for the period 2016 - 2017. METHODS: Antimicrobial susceptibility testing (AST) profiles on selected ESKAPE organisms and E. coli isolated from blood cultures from the public and private sectors in 2016 and 2017 were analysed. AST data were extracted from a web-based electronic platform created by the NICD. Drug-bug combinations following the World Health Organization's Global Antimicrobial Surveillance System guidelines were included in the analysis. RESULTS: A total of 28 920 ESKAPE organisms and E. coli were reported in 2016 and 32 293 in 2017 across the two health sectors. Proportions of some organisms differed between the two health sectors, such as E. coli (19% in the public sector and 36% in the private sector), A. baumannii (14% public and 4% private), P. aeruginosa (7% public and 11% private) and S. aureus (27% public and 17% private). Susceptibility data indicated changing patterns in both sectors towards an increase in non-susceptibility to carbapenems in K. pneumoniae (p<0.01). However, we demonstrated an increase in susceptibility to cloxacillin in S. aureus (p<0.01) in both sectors. CONCLUSIONS: The key clinically important finding is the rapidly decreasing carbapenem susceptibility among Enterobacteriaceae reported in SA, irrespective of sector. In addition, the analysis provides information that could be used to monitor the effectiveness of interventions implemented at a national level under the guidance and direction of the national AMR framework.